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2003 Toyota Tacoma pre-runner TRD 2x2 with auto trans. Just tuned up by toyota dealer maintainance shop. Engine seems to hesitate when going about 40 and kicked down to lower gear. It will pick up and go ok but sounds like timing is wrong and it is starving for air. Mileage is really bad, about 18 - 19 mpg on freeway at 2200 rpm.What is correct way to set timing and is that where I should start looking for solution?
Did you have this problem before or after you took it into the dealer?
What maintainance did the dealer do on your vehicle?
How many miles are on your vehicle?
At the 2200 rpms how fast are you going?
I purchased this truck from a local retired (75 yr old) bank president that I know. It has 150,000 miles on it - all freeway miles ( he has a BMW that he drives locally but had the Tacoma to transport his racing pigeons). He gave me the reciept that has 30,000 mi service including three part flushing and cleaning of throtle body inj. and cleaned and flushed gas tank and new platinum plugs and air cleaner filter an many other non-related services - almost $1200 worth. He has always gotten 16 - 18 /mpg but I know that having had other Tacomas that it should get 22 - 23 on the road at 2200 rpm which is 69 - 70 mph. I got all service records and receipts and it was well taken care of and is in immaculate shape!! The truck runs great except when you get on it it seems to have a real stumble from 3600 to 4200 rpm and then smooths out and really pulls smoothly.
I havn't done a compression check but did pull plugs and they are running all the same and are burning clean - just the color they should be.
When it stumbles from 3600-4200 rpms it that in all gears.
I've only noticed it in 3rd and 4th. It's hard to tell in 1st and 2nd, but it is deffinately not as smooth and quick as my two Camry XLE's were with the 3.0 V6 engines, but I know that they are a completely different injection system as well as many other differences. I've thought of putting in a K & N air filter in the stock housing as it seems like part of the problem is it's not getting enough air all through the top end. Would that be adviseable now or after we find the rest of the problem?
mat J ----Did you need some more information? They say that I am shut off now that 25 hours have passed but I think that you have the ability to help me. Let me know if you need more info.
Customer
Your expert has opted out of the question, would you like me to step in and assit you here?
Yes, I would appreciate the help. You can read my original question and the dialogue that followed and if you need any more info just ask. I will gladly pay for the help but mat J didn't give any answer for me to "accept" he just asked questions and they were good questions, I thought that he was getting close to coming up with something. Guess I was wrong.
Thank you.
Basically you have some issues with lack of power, some bucking and some issues with fuel mileage is what I gather. I do have a few questions here:
-I assume 3.4L v6 correct?
- You stated dealer just "tuned up", what all was performed on this service?
- 150,000 miles on truck-confirm this
-Has the dealer checked the truck for this concern or did you just notice this after the tune up?
-Checked for "pending" codes in the computer or check the data list readings with fuel trim levels?
Yes, it is a 3.4 V6. They did a complete flush of the throtle body injection system, new Platinum plugs, complete "three step" cleaning of AT, radiator flush, new air filter. Balanced and rotated tires. It does'nt buck it just acts like the engine has the choke come on about 3400 rpms when you get on the gas and then about 4200 - 4400 it takes off ok. The truck does have 150,000 miles on it, all (95%) on the freeway. It runs great otherwise. No, I have not taken it to the dealer for this yet nor checked for any computer codes.
Thank you for the reply. A few things need to be cheked here:
1- first I would recommend you have this checked on the dealer scan tool, there may be "pending" codes set that have not yet occured on a 2 trip logic to turn on the chek engine light. This is the forst place to start
2- data list, the dealer needs to check the data list parameters, ESPECIALLY the fuel trim readings, for example the fuel trim readings goal and purpose is to maintian a reading as close to zero as possible, the fuel trim readings can go as high as 19% without setting a code, this is basically a reading of if the engine is running rich/lean or stokeometric (perfect). (like big words?) If fuel trim readings are off then the forst thing that comes to mind here (and VERY common) is the mass air flow meter. This is the sensor on the air filter box, I replace these in bulk, very prone to contamination and failure, the computer uses this sensor to read air flow volume and temperature to the intake, it then calculates spark and fuel delivery based on this, so for example lets say you are on the freeway, you floor the gas pedal and try to pass a car- the air flow meter reads low volume of air so it retards spark timing and fuel delivery, can also cause hiccups/bucking/backfiring/many symptoms. $20 says you have a bad mass air flow sensor here.
3- Timing belt, this should have been replaced once already at 90,000 miles, I have seen these jump 1 or 2 teeth and not set any codes yet the truck has issues such as yours, make sure the timing belt has not jumped timing
4- tune up- you stated a list of things that were replaced, I also recommend at this mileage that the 3 spark plug wires be replaced also.
That's about all I can provide at this point, most of these items require the dealer to get involved so sorry if you were wanting a "do-it-yourself" repair but that's just my educated and honest take on your situation, usually you end up saving $$ by having a dealer properly diagnose a late model car compared to the $$$ you waste by throwing parts at it trying to guess a solution.
If you need some further input please reply back, it's near midnight here so I'm off to bed but I will try to check my messages at work tomorrow if you need to reply, if not then thank you for using just answer and allowing my input. Have a good evening.
ASE Certified Technician
ASE Certified, 10+ years experience, Lexus and Toyota Certified