engine misses it will stall at times

2004 CHEVROLET TRAILBLAZER

188,000 MILES • 4.2L • 6 CYL • 4WD • AUTOMATIC

SHELLY1983

MEMBER
4 POSTS

I have this vehicle and have changed the coil packs crank sensor spark plugs cam sensor fuel pump fuel filter. Valve timing cylnoide O2 sensors and throttle body cleaned. This vehicle is missing and the engine light is flashing now it was staying on after changing this no codes will pull up. Could u please help out? Also changed fuses. And catalytic converter replaced. What's next. Any suggestions?

Mar 26, 2017 at 7:10 AM

STEVE W.

✓ASE Certified Mechanic
15,200 POSTS

If the light was flashing there will be codes stored. It may take a Tech2 to get to them but there will be a code(s) there. It would also be possible for it to take a snapshot of the system and find the actual problem.

Mar 26, 2017 at 2:42 PM

SHELLY1983

MEMBER
4 POSTS

Im now getting miss fire on number 1 and 4 while checking these again changing them i noticed lots of oil on the number 5 plug. What's this now. Do i need another engine

Mar 26, 2017 at 6:27 PM

STRAILER

✓ASE Certified Mechanic
54,832 POSTS

Hello,

Lets start with a compression test, here is a guide to help you with that, then if okay, I would try replacing the mass air flow sensor. These parts can go bad without causing a trouble code and make the engine miss. With that many miles it needs it.

https://www.2carpros.com/articles/how-to-test-engine-compression

and

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Please let us know what happens.

Best, Ken

Mar 30, 2017 at 10:02 AM

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