hello ppl, i need help!! i have an 1986 camaro tpi 305 which idles really high then after afew minutes drops down abit. i have recently installed a new iac valve which made no difference, tried adjusting the tps but still idles really high. my tacho dosent work properly either, on starting goes straight to 5000rpm(thats idle!)touch the throttle at all and its of the scale so im trying to adjust it by how it sounds any help with getting my idle speed down to around 700 would be appreciated, but remember im not mechanically minded so explain as if u were talking to a 5 year old

 

Sounds like you need to do the Tach fix.

 

Have you checked for vac leaks?
Did you reset the min air when you installed the new IAC?
Without a accurate, working tacho you are up sh*t creek trying to guess what rpm the engine is at anyway

 

Not true.. If he has an auto he can figure it out an get close to correct idle. Im having some high idle issues myself. start the car cold 1,300. warm then restart an get a higher idle 1,500. I may need a new iac bc i did the iac tech an even with the iac unplugged it still idled high. Tps doesnt create high idle. heard egr can create it also. I never knew Iac cost so much! My dam. I hate these bugs with modified cars. And I have high Hc failed smog a few years ago. And like what the hell Hc supposed to be unburned fuel but people say it's from running lean. I cant seem to make since of that. I have had a tuner tune smog mph's with a wide band, but I have not went in smogged. One because of this high idle issue I need to fix.