i have a problem with my 5.7 in my 94 sierra loading up when i let off gas. i rebuilt throttle body, new injectors new sensors, new gaskets. also did a tune up and replaced o2 sensor in pipe past header. still loading up, any thoughts???

 

I'm having the same problem with a sierra that i'm working on!

it runs well for a few minutes and once it has run for about 10 minutes at idle, it wants to stall. All of a sudden the mixture gets way way too rich.

No bad codes have come up and the "throttle body has been swapped as well as the computer" according to the guy who worked on it before me. I can't be sure how much of this stuff is accurate about swapping parts out.

Compression is good and it doesn't overheat.

I was going to start with O2 sensor and throttle position sensor then move to MAPP sensor and so forth.

Any suggestions would be great and I hope you can get your problem resolved. It sounds like we have similar problems.

Thanks

~Tator

 

For anyone reading this-

I was able to fix my problem by replacing the coolant temperature sensor on the front of the intake manifold. it was $29 at Napa.

Hope this helps.

Tator