Engine miss, check engine light turns on after engine idled for about ten minutes

CWILLIAMS55

MEMBER
2003 CADILLAC DEVILLE
90,000 MILES

Replaced spark plugs, core packs and mas air flow sensor. Same problem. Not seeing any codes.
service engine soon light comes on after car has idled for about ten minutes. Light goes off when driving.

Monday, May 13th, 2013 AT 7:18 AM

4 Replies

CADIEMAN

MECHANIC
3,544 POSTS

If the service soon light is coming on it has to be setting a code. Have you performed a compression test on the engine?

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Monday, May 13th, 2013 AT 9:58 AM

CWILLIAMS55

MEMBER
2 POSTS

No compression test has been done.

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Sunday, May 19th, 2013 AT 5:55 PM

CADIEMAN

MECHANIC
3,544 POSTS

If the light is coming on then it has to be setting a history code. I can't help you without this code.

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Sunday, May 19th, 2013 AT 7:22 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Good evening,

I would start with a compression test. Make sure all the cylinders are within 20 pounds of each other.

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

The code would help but you need to do the basic tests first.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

You also could have injectors that have dirt in them. Additives have no effect on cleaning. you need to have them done professionally. that is when they disable the fuel pump and run the engine on pure injector cleaner.

Roy

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Friday, April 24th, 2020 AT 5:07 PM