Hello, I did the search feature. Car seems to be running rich, replaced the front two o2 sensors--passenger side was blacker than driver side--Right after the swap, we crank up the car(cold start), still had the same exhaust smell, (rich), i know it wasnt warmed up, but my step-son unplugged the map sensor while it was running, it didnt do anything, no change in idle-ran it maybe 30 seconds. Should there been some change in the idle, even if it was a cold start. Im just throwing parts at my car and thought maybe the map sensor was the culprit since there was no change in the cold idle when unplugged. Thanks Dwayne

 

So while the engines is cold should there be a difference in the idle when the map sensor is unplugged? Thanks Dwayne

 

Can you use a scanner to observe the MAP readings? That would take some guesswork out of it.

 

No i dont have/know how to use that. I was just blindly throwing parts at it. As i said earlier after the o2 sensor install, my stepson unplugged the map and it didnt seem to affect the idle on a cold start. Thats why i thought the map sensor might be the bad part from the beginning. Would it affect the idle?? Thanks Dwayne

 

Whe you disconnect the MAP sensor, the PCM defaults to an assumed MAP based on throttle position and RPM. Its unlikely the RPM would change.

Quit guessing..... we all rag on Mr. Goodwrench for blindly replacing parts in an attempt to fix things, then we go ahead and do the same thing. Find someone with AutoTap or some similar OBD-II scanning software and log the engine's performance from cold start through normal driving, through WOT blasts. Let someone who knows what they're doing take a look at it. Or send the data log to pcmforless so he can see if the tune needs adjustment.

You appear to have come to the conclusion its running rich by looking at the O2 sensors.... have you looked at the plugs, which would be a more reliable indication?

Finally, this belongs on LT1/LT4 Engine Tech, so I'll move it there for you.