Engine Idle Issue - TRIED EVERYTHING!

[KRemo]

Ok the ZuZu idles at 2k and will rev between 2k and 3k. Replaced TPS, FPR, IAC and intake gasket. There is no check engine light nor any codes. WTF?!?! :mado:

Please any ideas?

[LittleBeast]

bad gas? water in tank? fuel lines clog? fuel filter shot to heck? fouled spark plugs?

[newthings]

Remove the two bolts holding the EGR. Note if loose. Inspect for soot blowby on the gasket. Apply high temp copper coat on both sides of gasket (IF not broken) and retighten.
Cracked vacuum hose at connection.
Roy

[uncle_asa]

Did you cleaned your throttle when replaced IAC? And I'd say to check MAF performance.

[KRemo]

LittleBeast - that was one of 2 things the autoshop could tell me, it does not appear to be a fuel problem.

NewThings - that was the other thing they said - no vacuum leak detected.

Uncle_Asa - Yes, cleaned the throttle and the IAC and had replaced MAF. (Forgot to list that as one of the things replaced.)


An interesting update - We "manually" adjusted the IAC sensor and through trial and error, got it to idle at the proper idle speed in both park and drive. No check engine light either. I'm wondering why we had to adjust the sensor manually for it to work properly. Possibly the plug that the sensor plugs into is bad?

[iamironman]

Check this thread I just started...
http://www.vehicross.info/forums/showthread.php?t=16136

It could be that diaphragm that I (in a round about way) replaced... I had same symptoms you describe...