jim88-Z52

Took my plenum and runners off to fix what i thought was a small vacuum leak and when i put it back together i get 2000 RPM the second the car starts. It doesn't change during while driving, it will maintain 1800-2000 rpm with no load. I double and triple checked the vacuum lines and can't find a leak. The ECM, TPS, and IAC are all new. Went through the IAC reset procedure, no change. i datalogged a short drive from startup to finish with Datamaster and attached it for additional info. Engine is a 383, mild voodoo cam w/afr 180 heads, trans is M6. Prom was done by Scott Hansen and has been working fine. Any help appreciated, getting frustrated chasing this idle problem.

aklim

How did you reset the idle? If it was by the FSM method, well, you don't know much about what the ECM is seeing. I would suspect your system has an air leak somewhere but if you look at the IAC counts, you should see if it is at 0. If it is at 0 when it is at operating temp with everything but the motor off, turn the screw out to close the TB opening, rev and recheck the counts. Target count is 20. If after you close it as much as it goes and it won't get the target count, you have an air leak somewhere, I suspect.

dgantt

Are you sure you didn't create a bigger vacuum leak putting it back together. Those TPI system are hard to get sealed sometimes. You may have to smoke your intake and look for leaks.

aklim

Please tell me new gaskets were used. All of them.