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-   -   94 Z TBI Rough Idle Whwn Warm (https://blazerforum.com/forum/engine-transmission-35/94-z-tbi-rough-idle-whwn-warm-35414/)

duff 10-03-2009 11:30 AM

94 Z TBI Rough Idle Whwn Warm
 
Pulling my hair out on this one.

Simple Z TBI motor runs good cold. When warm it idles rough.
Can't really tell if it misses at high speed but seems to run well.

No Codes. Replaced plugs, wires, rotor, cap.
Cleaned EGR, new screen gasket, even plugged EGR with piece of tin to verify it was not leaking into intake.
Compression 185->195. Cleaned IAC but forgot to do a movement test by jumping ECM.
Replaced all vacuum lines - did find a cracked plastic connector to PVC on TBI.
Injectors appear to spray even cone shape no drips.

What else can I check? Dealership here will hit me real hard.

duff 10-05-2009 11:08 AM

I read a post saying that if you jumper wire to get the ECM codes, the IAC will extend all the way. When I did this the IAC didn't move at all. Maybe it was all the way out already ? I also read that if you apply pressure on the pintle side to side it will go back into the motor. It didn't seem to move much when I did that. Is this a good way to test it ? If so I suspect mine is bad. My IAC has a square 4 pin connector.


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