Mechanics

CHEVY MISFIRE

1999 Chevrolet Tahoe

Engine Performance problem
1999 Chevy Tahoe V8 Four Wheel Drive Automatic 108000 miles

I have had my Tahoe repaired at a local shop for a misfire code on cylinder #5, replacing:
O2 sensors.
Emissons hoses.
Cap, rotor, spark plug wires, spark plugs.
Complete Injector " spider".
Fuel filter and gas cap and sea foam in a tank of fuel.
This of course was all based on computer codes and complete diag. Scans, including live mode.
Complete compression test (was good).

Now after all this and $1910.00 my truck still has a misfire problem and in fact runs worse, with a blinking service engine soon light now.
Can you suggest what to do now.
I still cant register my Tahoe in Texas.
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Thunderwolf
June 8, 2008.




First thing you need to do is have the codes read, Autozone does it free, Post the results with the code number(s). Even if the service engine light is not on, there should be freeze frame data stored.
If it won't make it to Autozone, buy a cheap scanner, they can be had for 30-40 dollars, a good investment, since they cover all cars sold in the USA from 96 on.
If the light is blinking, it means possible damage to the converter. Service it right away!
1900.00 and still wrong? I would MAKE the shop get it right, and no more money!

Merlin2021
Jun 8, 2008.
Start with a compression test on the cylinders, then check fuel pressure with a mechanical gauge.

This could be a mechanical problem such as a valve or camshaft, or a bad/clogged injector.

Also have the code(s) read, but I would check compression on the cylinder in question at least.
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Mmprince4000
Jun 8, 2008.
Also there is a tech bulliten on the ECM groung corroding and causing misfire codes. Remove the ground strap and clean it up, and clean the mating surface, then reinstall it, and put a sealant over the repair.


http://www.2carpros.com/forum/automotive_pictures/62217_ECM_Gounda_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_ECM_Goundb_1.jpg


Merlin2021
Jun 8, 2008.
We are having the same problem. We have had in the shop numerous times. New fuel injectors, new fuel filter, new spark plugs and starter. The last mechanice said everything looked good and he could not determine the problem. He returned the car to us at no charge. But stilll has check engine light and will not pass inspection. We are desperate for a solution. Let us know if you find out anything new. We will keep you inform of our findings. IF ANYONE HAS ANY IDEAS PLEASE SHARE. THANKS!

Tiny
Est
Oct 12, 2009.
Did you try the PCM ground? Also post all the codes, just telling me you have codes does not help me to try to help you!

Merlin2021
Oct 12, 2009.

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