How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike S. Your Own Question
Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 7568
Experience:  ASE Certified Master Technician
Type Your Chevy Question Here...
Mike S. is online now
A new question is answered every 9 seconds

Chevrolet Suburban k1500: I have a 95 k1500 suburban 5.7 motor.

Customer Question

I have a 95 k1500 suburban 5.7 motor. Starts fine and idles fine in park. Step on brake it dies. Put in gear it dies. When moving at less than 30mph you have to pump the gas pedal like crazy to keep moving. Once it reaches 30-35mph it drives great.
Submitted: 2 years ago.
Category: Chevy
Customer: replied 2 years ago.
The cat is clear. Entire exhaust is fine. I replaced cts and iac. New plugs, wires, cap. Only codes are for random things like air conditioning issues and abs problems.
Customer: replied 2 years ago.
Also replaced map. It ran even worse with vacuum line hooked up on map. Wouldn't even idle.
Expert:  Mike S. replied 2 years ago.
Check the engine vacuum. First of all, start the engine and allow it to run for 10 seconds or so, then shut it off. Then pull on the vacuum hose valve at the brake booster and listen if you here it hissing. It should hiss, because the brake booster should still be holding vacuum. If it doesn't hiss, change that valve first. Also, try this, remove either end of that vacuum line to the brake booster and plug the end. See if the engine now stalls when you shift into gear. Remember though, you will not have any power brakes, so don't drive it. Let me know the results.Plus, if you do have a vacuum gauge, tell me the intake manifold vacuum at idle.
Customer: replied 2 years ago.
Yes there was vacuum at brake booster. Plugging it made no difference. As soon as i put it in gear it dies. If you pump the hell out of gas it'll move. Otherwise just dies. Still does great just idling. Could it be a transmission problem or problem with brake light switch? Neither seems likely because neither seems to cause any kind of issue once the truck is moving over 35mph. It sales along perfectly at 65mph.
Customer: replied 2 years ago.
I don't have a vacuum gauge and honestly don't have money to buy one right now. I've been told it could be a fuel pump issue but i figured it's not because you can rev it up in park and it runs so well once it's actually cruising along. Thoughts on that?
Expert:  Mike S. replied 2 years ago.
Isn't this fuel injected? Pumping a fuel injected engine isn't like pumping a carburetor. There is no accelerator pump.
What happens if you raise the idle some by pressing the gas pedal down some and then shift into gear, does it still die?
Have you messed with the distributor or ignition timing?
Have you checked the timing?
have you tried a new fuel filter?
Do you have a fuel system pressure tester?
Do you have a code reader?
Is the check engine light on?
No, I don't believe it's a transmission problem.
The only way it could be a brake light switch problem is if it's shorting out something like the ignition or fuel pump or computer.
Customer: replied 2 years ago.
Its TBI. Have not checked fuel filter because it seems to get gas just fine. It'll do 60+mph once its moving. Haven't done anything with distributer or timing. Yes i have a code reader. It only has codes showing for AC issues and ABS issues. Yes engine light is on. Yes it stays running when in gear if you give it just a bit of gas. It won't move though. You literally have to pump it continuously to get it up to speed. After 35mph it's fine. Drives like a normal vehicle. I got the truck already in this condition. No one had been able to figure out that's how I ended up with it. It's in too good of shape to junk. That's what previous owner was going to do with it. The motor was rebuilt 38000 miles a go. I guess it was all fine until this problem began a year ago. She took it to multiple shops while it was still halfway tolerable to drive. No one could figure it out. Then it got too bad to drive so she parked in the garage and it sat there until recently when i put it on a trailer and brought it home.
Customer: replied 2 years ago.
Even when in park it dies when you step on brake unless you're also giving it gas.
Expert:  Mike S. replied 2 years ago.
disconnect the brake light switch and see if it still dies when pressing the brake pedal.
Customer: replied 2 years ago.
I'll try it first thing in the morning and let you know. I'm willing to try anything at this point so if you think of anything else please let me know. Even if it seems crazy or remote.
Expert:  Mike S. replied 2 years ago.
Do you have those codes, especially them abs codes since since pressing the brake makes the engine die.
Customer: replied 2 years ago.
The codes were about front wheel speed sensors. I'm not home right now to get the exact numbers. Another one was something about air conditioner. And one was for the trans fluid temp sensor. I don't believe there were any others. If there were, they also had to do with the ABS.
Expert:  Mike S. replied 2 years ago.
Did you try disconnecting the brake light switch yet?
If so, what was the result? If not, let me know when you do and also those codes when you get them.
Customer: replied 2 years ago.
Ok. Unhooked battery then removed both plugs on brake pedal. Hooked up battery. Still dies when stepping on brake. Hooked up brake pedal switches again and went for a drive around the country roads out here. Came back and scanned codes again. #33,59,66,67,73,82. These seem to be mostly transmission problems but I'm not noticing any problem when driving it. I wondered before if torque converter was staying locked causing the slow take off and need to pump gas pedal. Once it's moving it does shift through all gears so the codes seem incorrect.
Expert:  Mike S. replied 2 years ago.
I was going to say it cannot be a transmission problem if you are simply pressing on the brake pedal in park but I thought, wait 1 minute, the torque convertor lockup runs off one of those brake switches. That makes me think, is it possible and if so are those 2 switches plugged into the wrong switch?
Expert:  Mike S. replied 2 years ago.
I see you were thinking the same thing. I just read the rest of your paragraph and seen that.
Expert:  Mike S. replied 2 years ago.
Is what you told me about those code descriptions what your tool says or did you look them up somewhere else?
Expert:  Mike S. replied 2 years ago.
I get code 33 as a mass air flow sensor high frequency.
Does that indeed have a mass air flow sensor?
Code 59 was the transmission temperature low.
66 was ac low pressure.
67 I don't have.
73 I don't have.
82 is ignition control 3x signal error.
Expert:  Mike S. replied 2 years ago.
That is what Chilton says them codes refer to.
This is from the Actron Code lookup site,
Code 33 Manifold Absolute Pressure Circuit High. So that has either a maf or map sensor.
Code 59 , actually it don't go no higher than code 55.
Expert:  Mike S. replied 2 years ago.
Let me check with Mitchell.
Expert:  Mike S. replied 2 years ago.
Mitchell says:
Ah ha
Expert:  Mike S. replied 2 years ago.
Here is that chart,
Customer: replied 2 years ago.
It has map not maf. I've looked tge codes up in numerous places. They all say something different. Like i said, it doesn't really feel like it's having a transmission issue and it shifts through all gears. Do you know if this has a crank sensor? I've read that it does and I've read that it doesn't. I haven't had time to actually look it over to see. There seems to be numerous possible locations for it IF it does have it. I can see why no one has been able to fix it. Too many possible causes and no consistent information about this truck. Everyplace has different information.
Customer: replied 2 years ago.
The brake switches are hooked up cortectly. There's only one way to hook them up. The lower one has three pins and the upper only has two.
Expert:  Mike S. replied 2 years ago.
Does this have a distributor? If so, I don't believe it has a crank sensor, but I will double-check.How about that 67, TCC SOLENOID CIRCUIT CHECK - 4L60-E TRANSMISSION
Expert:  Mike S. replied 2 years ago.
We both were just thinking about the brake switch and the torque convertor lockup solenoid.
Expert:  Mike S. replied 2 years ago.
Well, autozone says it does have one and it's at the rear of the crankshaft pulley, mounted in the engine block.
Expert:  Mike S. replied 2 years ago.
If it has the DI distributor then it has a crank sensor, if it has an HEI distributor than it does not.
Expert:  Mike S. replied 2 years ago.
The Distributor Ignition (DI) system consists of the distributor, hall effect switch (camshaft position sensor), ignition coil, secondary wires, spark plugs, knock sensor and the crankshaft position sensor.The General Motors HEI system is a pulse-triggered, transistorized controlled, inductive discharge ignition system. The entire HEI system (except for the ignition coil) is contained within the distributor cap.
Customer: replied 2 years ago.
Yes it has the distributor type ignition. Today it won't even idle in park. It's hard to start and when it does start, It's very rough for a couple seconds then smooths out. It'll run like that for a minute or so and then die. No new codes and nothing is different in any way. When It's idling you can rev it up by feathering the pedal until it reaches about 2200 and then it's fine. You can run it all the way up close to red line. But up to around 2200 it coughs and gags nonstop.
Customer: replied 2 years ago.
It's been showing code for map sensor continuously but I've replaced it. Any ideas on that?
Expert:  Mike S. replied 2 years ago.
What is the intake manifold vacuum at idle?