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ironmike
ironmike, ASE Master tech
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96 monte carlo: v6..a major sluggish problem in the motor/trans

Customer Question

I have a 96 monte carlo v6 138k. I have been fighting a major sluggish problem in the motor/trans for about 8 months. I have almost given up on it. I have changed the following. Battery, fuel filter, fuel pump, fuel regulator, coil pack, ignition, plugs, wires, and CAT. We have seen a O2 sensor code off and on, but it is never always there. The car runs randomly fine. Every other time on speeding up the car won't hardly move. The only way to get the car to pick up speed is to push it to the floor. Fuel pressure is around 36-39 when the car is running. I was thinking for awhile that maybe it was the torque convertor but it's acting like it should on the hand held scanner. I am starting to put my attention on the fuel injectors.
Submitted: 5 years ago.
Category: Chevy
Expert:  ironmike replied 5 years ago.

Greetings,

You may be right with the injectors. GM makes a cleaner that you run through the system, best out there. I would want to see what the o2 sensors are doing, with those miles you cannot rule them out. If you have the 3.8L You may have an issue with the intake or plenum. The plastic around the egr melts and coolant enters the intake where only the egr should.

good luck

Customer: replied 5 years ago.
Our 96 is a 3.1L. I forgot to mention that in the first post so the intake shouldn't be plastic. We have had the car on a buddies snap-on scanner which at that time showed the o2's were in range. One of them might be jumping out of range once in awhile causing the light, but we have had the o2 light issue for over two years and this performance problem has only been for the past six months. I guess I really shouldn't say performance problem, because if you stop at a stop sign, you get to about 20mph and at times you are concerned if you are going to make it to the next block or not. I personally thought it was a fuel pump/filter problem. I was confused after changing those with no luck. Thats when I changed spark plugs/wires, then changed out the coils and ignition with a known good set, will still no luck. For the past 2 months, I have been running sea foam and other stuff through the tank. Enough to kill a horse I'm afraid. Up until this problem, the car was an everyday driver. Since then we have completely removed the CAT trying to quickly pin point the problem. It's louder, but reving it up in neturel the motor just doesn't sound smooth. Last but not least, I thought I should add something else to confused the issue. When the car does 'act up' and you feel like your running out of gas, or not going to make it to the next block because somebody tied a 10k pound trailer to the bumper, if you change gears to neturel the motor will rev up freely with out hesitaion, back it drive and it's sluggish again. So two months back i was leaning on transmission issues or something that only happens under load.
Thanks
Expert:  ironmike replied 5 years ago.

Greetings,

I would check for a sticking egr valve, cleaning the egr usually helps with performance along with the fuel service and throttle cleaning. I will continue to check out other causes for you.

Expert:  ironmike replied 5 years ago.

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 99-06-04-005B

Date: September, 2001

TECHNICAL

Subject:
Driveability Symptoms Due to Clogged Fuel Injectors
(Clean Injectors)

 

Models:
1994-1996 Buick Regal
1994-1999 Buick Century
1994-1998 Buick Skylark
1994-1996 Chevrolet Corsica, Beretta
1995-1999 Chevrolet Lumina, Monte Carlo
1996 Lumina APV
1997-1999 Chevrolet Malibu, Venture
1994-1996 Oldsmobile Cutlass Ciera
1994-1997 Oldsmobile Achieva, Cutlass Supreme
1996-1999 Oldsmobile Silhouette
1997-1998 Oldsmobile Cutlass
1999 Oldsmobile Alero
1994-1999 Pontiac Grand Am, Grand Prix
1996-1998 Pontiac Trans Sport
1999 Pontiac Montana
with 3.1 L or 3.4 L V6 Engine (VINs E, J, M - RPOs LA1, LG8, L82)

 

This bulletin is being revised to update labor time allowance for labor operation J5645.

Please discard Corporate Bulletin Number 99-06-04-005A (Section 6 - Engine).

Condition

Some owners may comment on driveability symptoms of long or hard starts, chuggle, rough idle and light or intermittent misfire. The malfunction indicator lamp (MIL) may also illuminate.

Cause

Due to various factors, the fuel injectors may become restricted. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.

Correction

Fuel injector restrictions, deposits, can be cleaned on the vehicle, using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened.

Notice :

^The recommended mixture amount of GM Top-Engine Cleaner has been increased from 5% to 10%. This increase was implemented to improve the effectiveness of the injector cleaning procedure. Follow the cleaning procedure carefully to minimize the risk of fuel system damage.

 

^GM Top-Engine Cleaner is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners, while effective, may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Top-Engine Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.

 

Important : This bulletin recommends the use of pre-measured containers of GM Top-Engine Cleaner, P/N 12346535, - U.S. USAGE ONLY.

 

Pre-measured containers eliminate the need to measure the amount of GM Top-Engine Cleaner being added to the J 35800-A, injector cleaning tool. In Canada, use P/N 992872. It will be necessary to measure and dispense Top Engine Cleaner into the J 35800-A, injector cleaning tool.

Parts Information

Parts are currently available from GMSPO.

Warranty Information

Expert:  ironmike replied 5 years ago.

Greetings,

I know with the older GM transaxles they used to have o/d problems and stick in overdrive. We would just unplug the trans connector. With some vehicles the torque converter gets dirt and worn bushing/clutch material stuck in the torque converter and at cruising the converter locks up for o/d but stays in o/d. This could cause stalling and no power. Take a look at the fluid color and smell ( dark and burnt) if it's dirty I would try a flush. If it's really bad a flush might cause the trans to stop shifting(no clutch material)

good luck

Customer: replied 5 years ago.
A local mechanic here is a friend of mine and he told me that from 110k-120k the fuild turned from a light pink to a red. He said he would not trust changing it. When I brought up the torque convertor issue (locking up prematurely) he said possible but very unlikely if I don't feel it slowing down. He and five other people said it would feel like a manual in 5th slowing down. This problem is normal after the first three miles, stop at a stop sign, once you start moving again you get to about 20 mph and you feel something is not right. If you push harder on the pedal it's like the car is running out of gas. At that time I can put it in netural and rev up the motor freely, back in drive again and it's back. If you push the pedal down all the way, the motor revs up and it hesitates for about 10 seconds and starts picking up speed. Once in awhile it will then come out of it and not do it for the rest of the day. Possible to add some seafoam to the tranny fuild to recondition? Still leaning on injector issues.
Customer: replied 5 years ago.
I was thinking about what you said with the tranmission. Since I hear the motor reving up and it's still acting up, that could mean it's in the transmission. If the transmission fuild is old, 138k and I am not even sure if it's been changed, is it possible that the transmission filter is half/3/4 of the way plugged up? What does a car/truck acted like when the transmission filter has restricted flow?
Customer: replied 5 years ago.
I also reread your comment about the O/D problems these cars have been having. I wanted to comment on your issue about the converter and the o/d locking up and staying locked up. This problem (when it happens) starts is around 20mph. It will struggle and struggle to pick up speed all the way up to cruising. The more you push on the petal, the worse it gets. You can slowly gain speed by letting off the petal and let it cuise up to speed slowly by itself but as soon as you push to hard it doesn't pick up speed again. Pissed off at this point, this is when I realized that if you slam the petal down, the motor will rev up and after 10 seconds of slugging, it will snap out of it and pick up speed, then sometimes it doesn't do it for the rest of the day.
Expert:  ironmike replied 5 years ago.

Greetings,

I would love to see on a scanner what it is doing when the loss of power is felt. It happens at 20 mph , which makes be believe it's less trans and more air/fuel issue.DESCRIPTION
The Mass Air Flow (MAF) sensor measures the amount of air which passes through the throttle body. The PCM uses this information to determine the operating condition of the engine, to control fuel delivery. A large quantity of air indicates acceleration, while a small quantity indicates deceleration or idle.

The scan tool reads the MAF value and displays it in grams per second (gm/s). At idle, it should read between 4 gm/s-7 gm/s on a fully warmed up engine. Values should change rather quickly on acceleration, but values should remain fairly stable at any given RPM. A failure in the MAF sensor or circuit should set DTC P0101, DTC P0102, or DTC P0103.

I would pull some spark plugs and tell me what color are they, black or white.

According to alldata your fuel pressure should be 48-55. That is enough to cause a issue, you said you have 36-39. Try disconnecting the fuel pressure regulator vacuum hose, it should boost the pressure.

good luck

Customer: replied 5 years ago.
Yes when it happens, you can normally feel it starting right after you stopped and starting moving again, around 20-30mph, or if it's currently doing it, trying to pass or speed up at any speed. That is why everybody so far ruled out torque convertor unless it was locking up to early causing the drag down. I have never received any other code other than the o2 sensor about six months ago and after that we have not seen it or any other code. We were dealing with very hard starting. The engine would crank for about 20 second before starting, it would then surge and sometimes die. If it didn't die, the RPM would level back out and be fine after a few seconds. I changed the fuel pressure regulator and that fixed it completely. Then two weeks later had this problem start. Not sure if it's related. I have changed the fuel pump. Old pump and new pump both shows the same results, pump priming 42psi, pump off 39psi, engine running 35-37psi. Increasing up to 42-45psi when reving. Fuel pressure regulator hose removed 45psi. I have alldata and it shows GM made a change on the current 48-55psi. They have been changing a lot of fuel pumps for no reason. They have lower that number to 41-47psi. Here is the following information:

Technical Service Bulletins
Bulletin No: 61-63-10

This revision for 1996 3.1L VIN blah blah blah
Use the following specification in order to properly diagnose the fuel system pressure:
Fuel system pressure specification 284-325kpa (41-47psi)

I am sure you can look up that bulletin if you need more information. I can't copy and paste from alldata. Also I did by chance have a fuel pressure gauge hooked up to the car once when this problem happened, but the fuel pressure didn't drop.

I also did disconnect the pressure regulator hose about 4 months ago and drove it that way just to see and it still does it.
For the record, I have changed the following:
battery new
coil packs used known working
ignition used known working
spark plugs new
spark wires new
fuel filter new
fuel pump new
fuel pressure regulator new
and removed the converter

I never knew the correct readings of the MAF sensor to know if it was out of range or not, but I will keep an eye on that the next time we work on this car.
Expert:  ironmike replied 5 years ago.

Greetings,

I have worked for independant shops and have seen aftermarket parts e bad new. I also saw how guys at the dealership would think unless the part was GM it won't work. I'll keep searching, this is a tough one. I know when you have problems like this you can never go over the basics enough or rule out parts that were replaced.

good luck

Customer: replied 5 years ago.
That is why I thought it was a fuel problem because after I changed the regulator and two short weeks this started acting up. If I wouldn't have thrown the old regulator I would have put it back in and delt with the hard starting for a week or so just to see if it would stop doing it.

Unless there is crap in the fuel line somewhere. You would think that unhooking the pressure regulator hose would not raise the pressure if it was just resriction in the line but it does, 5-10psi raise.
Expert:  ironmike replied 5 years ago.
That is normal, that is why I said to remove vacuum hose to the regulator.I will still kep checking.
Expert:  ironmike replied 5 years ago.

Greetings,

As I was looking through alldata I worked with a guy at a Chevrolet dealer. He worked at Cadillac before this, he told me about a car he worked on with etch assistance. I forget the model and make but it was GM. It was under warranty and had a stalling issue on turns. The GM tech line told him to replace several parts. The last was the fuel rail, that is what caused the stalling. Maybe you could get from a junk yark the fuel rail,regulator, injectors(the whole assembly) and see what happens. If it feels like fuel you may be right. Just a thought.

Customer: replied 5 years ago.
I am very curious to know why the fuel rail alone caused the stalling. Fuel goes in and to the injectors and back out the regulator. The fuel rail is nothing but a supply tube so that is interesting.
I can not pin point that "turning" is the cause of the problem because I took it out once after it was sitting for 4 months and left my house and ran in 3/4 of a mile to the first gravel road (left turn) and went south two miles. Another left turn and back east 2 miles, another left and north two miles. I was stopping and starting again this whole trip. After finishing coming north the 2 miles I stopped at the stop sign, pissed off that the problem was not acting up, turn left once again to head back to my house and not more than 20 mph and there it was. I didn't think I was going to make it back to the house. This car has never stalled stalled accept the hard starting issue after the motor has been shut down. I took that as a common 'lost of pressure' while the pump was off. If I cycled the key several times (pump) and then started it, it would start better. Once I changed the regulator, that problem was gone, then like I said, two weeks later I had this problem. Car always starts great now though. I do have another rail and injectors (not sure how many injectors left) from a 96 pontiac 3.1 that would fit. I wish I would have thought to check fuel pressure with the old regulator and compared to the new regulator, but I'm afraid the old one is long gone and the one off the pontiac has been tried, same hard starting issue so I put the new one back in.
A buddy of mine is convinced it has something to do with too much pressure in the motor. He said when it's doing it and I step on it, and can hear the motor rev up, the motor is fine, but it fighting something. That is why we took the CAT out to make sure it was not plugged. Although he was convinced the CAT was plugged as well which it wasn't.
I was leaning on the lines of maybe a gasket out building up to much pressure in the motor after it has been ran for awhile, but I guess that doesn't explain why it's random unless at different points the motor swells and opens/closes the gasket. No water in the oil, and have not noticed any odd color spark plugs when I changed them. They all looked dark brown if I remember right. Don't quote me on that.
Expert:  ironmike replied 5 years ago.

Greetings,

I just has a problem with my car, very unusual. I was driving down the road and all of a sudden it started smoking, pinging and no power. I barely made it home. After I shut the car off, I tried to restart and it soumded like it locked up. I thought it didn't overheat, no oil light. I checked the coolant, fine. I let it sit and tried to start it again later, a few more rotations but the same thing. Now I am thinking it has to be an injector. I pull the spark plugs and crank over to see which one. Cylinder #1 fuel come pouring out, disconnect the plug and still coming out but as a mist. I pull the rail and check for cracks, plugs on the even side are lean and rich wet on the odd. I call the dealer and he has one injector and I get the plugs. Pop it back together and thank GOD it runs and after a few days pretty good. I have never seen a injector let loose like that. My car is a 1994 concorde 3.5L.

Customer: replied 5 years ago.
I suppose those little metal clips that hold the injector in don't last forever huh? Trying to add your issues with my issues and wondering if I should start at looking at the injectors. A buddy of mine wanted me to OHM each injector to make sure it's up to the correct level for one or after spending $800 in this car which is almost no longer worth it, going to a junk yard and buying as you said, fuel rail, injectors, and regulator and trying it again. I am about ready to give up on this car. If it wasn't for dropping insurance while we were working on it, I'd trade it in for "cash for clunkers", but since they require 1 full freakin year for insurance, screwed on that deal.
Expert:  ironmike replied 5 years ago.
wow one year, didn't hear that. Government finally got smart, to little too late.
Customer: replied 5 years ago.
I did pull the egr tonight. Doesn't seem to be sticking but I will clean that out and also take off the air intake and clean the throttle body tomorrow once I get some carb cleaner. I think we have some MAF cleaner out at the shop as well. I will pull that apart and spray that a few times.

I still don't understand why these cars and most cars are made to trigger a SES light and problems like this don't show up period. I was told fuel is a big thing that doesn't show up on the computer other than misfiring but I don't believe this is a miss when it happens, just a serious drag down.
Customer: replied 5 years ago.
Well today I pulled it in and took off the MAF and hose and cleaned the MAF with MAF cleaner about three times. I cleaned the sensor inside the tube as well. I took off the thing right above the throttle sensor (punger of some type?). I cleaned that and gave it a quick lube spray because it was sliding kind of hard. I sprayed out the throttle pretty good and put it all back together. I took it on the mile hike I told you about, and when I left the last stop sign I felt a little hesitation but no serious drag down like before. I left off and pushed again and it seemed ok. I put about 8 miles on after that and did not feel anything but a little hesitation on speeding up. That could be from no CAT or sitting for 4 months. I am not ruling the problem fixed yet because it didn't do it from time to time for a few days. I will have to start driving it now though and see if it comes back. I am very curious to see what the injectors look like though. I know the CAT should go back on due to the needed back pressure. Sitting in the driveway and reving up the motor, when it slows back down you can hear some pretty good popping.
Customer: replied 5 years ago.
I also took off the EGR value. That didn't seem like it was sticking but I sprayed some carb cleaner in there and worked it around for about ten minutes over and over moving the valve in and out.
Expert:  ironmike replied 5 years ago.

Greetings,

that would make sense since this seems to be an intermittent problem.

Customer: replied 5 years ago.
I took it out for a drive again tonight. The car ran for about 8 miles total and drove just perfect. The last turn heading to my house it did it again. Problem not fixed. I paid attention to everything I did. I did not realize it until I started thinking about my direction turns, I ended up making one big square and all of my turns expect for two were right. The last turn was a left and that is when it did it. Left hand turns fatal to carlos or is it just me?
Did you get any more information on the GM car that needed the fuel rail replaced in order to correct the stalling? This almost sounds like my problem, minus the stalling and I do remember a time or two that it acted up just stopping at a stop sign and still going straight.
Expert:  ironmike replied 5 years ago.

Greetings,

I don't know if I will see that guy again. He used to work with me at the Chevrolet dealer. If it makes you feel better they replaced many parts under TAC hotline advice. They even missed with the engineer, the rail was a last guess.

Expert:  ironmike replied 5 years ago.
I would check the egr one more time. I have tried to clean them and most of the time they would stick again.
Customer: replied 5 years ago.
I was tempted for the last 20 minutes just to pull the car in the garage and rip the injectors out and take a peak at them. As for the EGR, a light should come on showing it was out of range. Should being the key word there. We have a snap-on scanner out at the shop. I might clean it, and if it acts up again plug it in and go driving around. How could the EGR be causing such a serious problem though? A little hole returned the exhaust, that doesn't really seem like it is a big enough issue to make the car feel like it's running out of gas or 90% of the air filter is plugged.
I did find my extra fuel rail from my 96 pontiac 3.1 with 4 injectors left on it, condition of the rail and injectors unknown. They have been sitting in the shop for over a year.
Expert:  ironmike replied 5 years ago.
a vacuum leak can do things like that, especially when you have a map sensor. In extreme cases i would make a plate and disconnect the egr completely.
Customer: replied 5 years ago.
Well I removed the injectors last night. They looked fairly clean. I took them out to the shop today and ohm them and three were around 12.5-12.6 and the other three were 12.8-12.9. While I was out there, I took my old rail out and tested the four left on that one and they were 12.9-13.1. I switched rails and used two of my injectors that had the highest ohm and plugged it all in. Seems to be running ok so far, but it did last time. I will take it out again tonight for a little bit.
Expert:  ironmike replied 5 years ago.
good luck
Customer: replied 5 years ago.
Well same problem. I took it out tonight after changing the fuel rail and 4 of the 6 injectors. I got half way to town and it had to kick out of O/D to produce power on a very small hill. I turned around and it spit and slugged trying to pick up speed. Once again, slam on the pedal and it revs up and comes out of it. What else do you have for me?
Expert:  ironmike replied 5 years ago.

Greetings,

I remember once replacing a MAP sensor on one with an aftermarket brand. It was wrong and caused some performance issues. I have also seen(chrysler) some MAP sensros be bad and not set any codes. How is the map. The more I read the past posts I see what looks like an issue that might be hid by the extra fuel given on cold running. I am still looking

Customer: replied 5 years ago.
Very interesting. I ran across this forum I thought you would be interested in reading. Another 96 monte owner wrote:

I'll start a new thread that's more on topic. The car is a 96 Monte Carlo with the 3.1 v6. I'm going to give up on the plugs being the problem. Took the thing for a ride and these are now the symptoms. First of all it idles fine through the entire warm up cycle. When you start out cold it runs pretty much ok. At about 2 or 3 minutes into the ride it starts to accelerate like crap. I mean really bad. First gear is not so bad but after shifting into 2nd it feels like someone tied a two ton trailer to the back. It will barely pick up speed. After it's completely warmed up it runs fine. You can drive it for hours and it performs flawlessly. I would guess it's something with a temperature sensor. Any help is appreciated.


This sounds pretty much like my problem, minus the fact that when it warms up. I do believe my problem happens warm or cold. Reading the post farther, the guy found out it was the knock sensor. He unplugged it and it has been running fine for 6 months. Maybe I will have the same luck, I unplugged it last night.
Might call the junk yard and ask about a MAP sensor as well just for something to do.
Customer: replied 5 years ago.
I don't want to run to many things by you at once here, but I just ran acrossed information looking at MAP sensors. One guy said:

unplug the dam thing ( map sensor) and leave it unplugeg the computer will reset itself to the basic settings. if it runs fine replace the sensor if you still have the problem its something else.

Will the computer run the basic settings if it's unplugged? I called the junk yard and they have them for $35 but I honestly don't want to spend anymore money in this car unless I know it helps. It's getting old seriously. Minus the short few test runs the car has been sitting for almost a year now.

I also have a good used TPS that I installed this morning.
Expert:  ironmike replied 5 years ago.

Greetings,

Not sure about disconnecting the map electrically. I would think if you pull the vacuum and plug the line it should simulate low vacuum and cause it to run rich.

Customer: replied 5 years ago.
Ok, I have stolen my buddies snap-on tool scanner and gun point and I have it until he calls and wants it back. I made a mistake last night and unhooked the TPS and took it out for a drive. I have unhooked the knock sensor and by accident I unhooked the fuel pump/engine oil pressure indicator switch but plugged it back in. I am running with the knock sensor unplugged right now. No problem so far, but the scanner brought up the following codes:
p0122 - TP or APP sensor 1 ckt short/low
p0327 - knock sensor 1 signal short/low
p1107 - map sensor ckt intermittent low
p1115 - ect ckt intermittent high volts
p1112 - TP ckt intermittent low volts

The knock sensor is explained because it's unhooked. Both p0122 and p1112 can be explained by me unhooking the TPS and taking it out for a drive and since I unplugged the one over from the knock sensor, alldata shows it was a fuel pump/engine oil pressure indicator switch, and I think that might explain the p1115, but I never unhooked the map sensor. I unhooked it while the car was off and I was changing the fuel rail and injectors, but that was it.
You said you would love to see it on a scanner, I have the scanner, what numbers do you want, idle, 55mph, or otherwise?
Expert:  ironmike replied 5 years ago.

There is a common thread with the tps and the map, the 5 volt ref feed. It could be a bad connection at the pcm or map or just a bad map.

MAP Sensor Circuit

Customer: replied 5 years ago.
I have looked at the volts when the car is running and it is getting correct voltage I believe. It idles around 1.37volts and hitting the gas it jumps up to 3.xx volts. Running around 55mph it holds at about 1.30 volts. So it seems to be working, I am thinking maybe it's the MAP itself. I dont know much about MAPs and how they are suppose to work (what voltage - when) but it seems to be ok to me unless the MAP sensor itself is not sending/receiving the correct info.
Customer: replied 5 years ago.
I should also note that the knock sensor is still unplugged and I drove it most of the day with no problem. Small hesitation while accelerating but nothing like before at all and that is most likely because the sensor is unplugged and it's defaulting the normal volts.
Expert:  ironmike replied 5 years ago.

Greetings,

Knock sensor would make sense for loss of power and being electrical it could get worse with heat. With the scanner you will see the timing retard when the hesitation happens. Usually they set the light, haven't seen one cause a hesitation. But you learn stuff all the time with cars, I will remember this one.

Customer: replied 5 years ago.
Lately I have been feeling it within the first 10 miles of driving, highway or city. I will give it a couple days and drive it instead of my diesel pickup and see if the problem is gone or not.
Expert:  ironmike replied 5 years ago.

I hope this is it.

Customer: replied 5 years ago.
I thought I better fill you in on an interesting day I had. I went up to the junk yard like planned to pick up a MAP sensor. I brought the sensor back home and hooked it up, decided at that time to plug back in the knock sensor. I drove to town (8 miles) and it started doing it again. I had the snap scanner on it, but I could not see anything abnormal yet. While I was leaving town it did it again, and I started paying closer attention to all the numbers. I noticed the knock retard degrees was sitting at 2-4-6-2-0. I thought I have never seen that move off of 0 before. I stopped at a stop sign and it read 0, once I started moving and it acted up, the numbers did it again, 2-4-6-8-10-0. Once it hit 0 again it stopped. I called a buddy of mine and I'm sure you already know, the ignition was retarding the timing from the knock sensor. Makes sense since I had it unplugged it never did it. I pulled off another knock sensor from a v6 1996 truck and installed it. When the knock retard on the scanner came off 0, that is when my problems start. Maybe it's in the motor and maybe it was the sensor. I will find out when I take it for a drive later tonight. At least I figured out what was causing the problem! You might want to write this down in your book for future issues. It was very interesting and after 10 months of off/on work, I'm glad at least I know WHAT is wrong and why.
Customer: replied 5 years ago.
Installed the other knock sensor and it still does it.
Customer: replied 5 years ago.
Last night I started playing around with it again and I noticed I had a slight miss on random cylinders. I started reading up and both missing on random cylinders and knock retard can be both caused by running lean. I start looking at vacuum lines and could not find anything. I did notice that yesterday my front o2 sensor was flying around between 95-890 something like it should, today i noticed it's hanging above 890 and it will only jump around when you play with the throttle, and then it goes right back up to 890 or so.
Expert:  ironmike replied 5 years ago.
Maybe we are back to the map or vacuum leak from the egr.
Expert:  ironmike replied 5 years ago.

EGR Valve
Notes
Rear Of Engine

If the egr looks like this, from what I remember when they start to fail or stick you can try to clean them but usually wind up replacing them.
Customer: replied 5 years ago.
I have cleaned the EGR valve twice. I have also replaced the MAP sensor.
Expert:  ironmike replied 5 years ago.
Try disconnecting it
Customer: replied 5 years ago.
I will give it a shot. The scanner does show it's shut when it's suppose to be, but I will give it a shot tomorrow.
Expert:  ironmike replied 5 years ago.
The vacuum style was more reliable and cheaper to replace.
Customer: replied 5 years ago.
Well after my daugthers birthday part on Saturday I started working on the car again. The knock sensor is picking up a knock and retarding the timing. I take it timing has been my whole problem after all. If I unplug the knock sensor the car runs perfect. I have replaced the knock sensor and it still does it. I unplugged it again for the time being. I did notice like I mentioned that the car has a random misfire on almost all cylinders but favors 2-3-4. It's enough to see the information live, but not set a history or code. When I unplug the o2 sensor the car runs rough for about 15 seconds and then levels out. The scanner shows it defaults to 420-440 range and there is no more misfiring at all. The car runs smooths as can be with the o2 unplugged. I thought that maybe the o2 sensor was causing the car to run more lean and cause the knock sensor to pick up knocking so I replaced the o2 sensor and the problem is still there. When the car runs perfect, the o2 and knock sensor is unplugged and the o2 readings are o2 1 420-440 o2 2 775-840. I remind you the convertor is gone.
Expert:  ironmike replied 5 years ago.
Maybe the engine has some piston skirt slap. These engines were known for that and a wrist pin noise.
Customer: replied 5 years ago.
I read that too in alldata. You can hear the knock when it's cold, even worse during the winter, but I guess I can unplug the knock sensor and be done with it, but what do I do about the o2 sensor and the missing. Should I just leave that unplugged as well and just burn a little more gas with it running rich?
Expert:  ironmike replied 5 years ago.
I would research and get a hotter spark plug.
Customer: replied 5 years ago.
I did change spark plugs but I rechecked them. The original plugs were AC Delco 41-940 and they were replaced with AC Delco R42TS bought from NAPA. They told me they would fit/work ok. My original problem with the knock retard was still there afterwards and the car seemed to run the same with either old or new plugs. Looking at the ACDELCO sight for plugs, the R42TS only show working for car up to 1989 so I don't know why they said these would work.
Expert:  ironmike replied 5 years ago.
That is a colder plug R42TS, than R46TS. I just refreshed my memory from a delco site. The high the 2 # XXXXX hotter the plug. GM does make a rapid fire plug for this engine.
Customer: replied 5 years ago.
<p>So do you really think I should buy the hotter plugs or is it just another thing to try? What do they recommend for these cars?</p>

I justed measured the plugs because I thought there was something different between the two of them and the new ones are about 1/2" shorter than the ones that came out. Not sure if that makes any difference or not, but the new plugs will not be down as far in the head as the ones that came out.
Expert:  ironmike replied 5 years ago.
Length is important, it might lack in power with those. I would probably try changing the gap but change the plugs no. I think changing the heat ranges was done more in the old hot rod days. I would live with the miss if not too bad if unpluging the knock sensor cured the hesitation.
Customer: replied 5 years ago.
If the length of the spark plug thread is important, then that might be the cause of the slight miss. I will keep the knock sensor unplugged and maybe start looking around for a different set of spark plugs. Those r42ts or whatever they were, you search for them on the acdelco sight and the applications they list, there is nothing newer than 1989 for those plugs. Then if you check other places on the net, some sites don't list anything newer than 1978. Napa was out of the current plug for that car but they told me these would work. Retards. On another note, NAPA spark plug wires suck. Two sets now pulled apart on me.
Customer: replied 5 years ago.
Well I went over to NAPA today and they told me that the spark plug they gave me was a cross over from the original. So I am going to play around with everything for a bit longer.

I noticed you were a diesel tech as well. I have a 2006 Dodge Ram 2500 5.9L Diesel with an automatic transmission. How hard would it be down the road to swap it with a 6 speed manual?
Expert:  ironmike replied 5 years ago.
I have no experience in doing that, But was once involved in converting a 70 something duster from auto to stick. The pedals were the worst so I could imagine the slave system for the clutch with the pedals through the fire wall. This engine should have a dual mass flywheel(expensive) although I head you can convert to the normal flywheel. I would fist ask why? I say sell and buy another truck.
Customer: replied 5 years ago.
Just because I like my truck. I bought it new here about 2 1/2 years ago and I made sure the oil was changed, broke in correctly and taken care off. Plus I could find a truck just like mine, same miles, same condition and still have to pay $$$ because of a trade.
Expert:  ironmike replied 5 years ago.
Seems like too much work and when you want to sell it will show on options(at least in the chrysler system)

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