gpss97

i just replaced my iac earlier today, and it still wants to die sometimes at idle and especially with the ac on. i only drove it for a few mins though. my question is, does it take a lil bit of driving for the ecm to learn? or iac? if not is there something else that could cause the car to not want to idle? no vacuum leaks, new wires and plugs, one day old. i'm getting frustrated with this thing. any input would be appreciated. thanks
mike

shoebox

You should do a reset when you install a new IAC. The computer does not accurately know the pintle position until you do.

gpss97

ok after driving for a while, it idles correctly about 98 percent of the time still wanting to drop a few times. but the main problem is it still will not even try to hold an idle when i turn the ac on. the rpm needle drops as fast as if you turn the key off, so i have to keep my foot on the gas. i never had this problem before i rebuilt the motor, so i have no idea what would be causing this. at first i thought it was my old compressor trying to lock up due to moisture, so i put a diff compressor, and i don't feel such a shock of load when the i turn the ac on anymore, but it just still doesn't want to idle.

feenix88

Check your vacuum, check your rocker adjustment (which affects vacuum), check all your vacuum lines

Injuneer

Put a scanner on it, and find out what IAC counts the PCM is calling for, and how they respond to the A/C being turned on. Sounds like the IAC may not be responding, the IAC passage may be plugged, or the IAC counts are already maxed out.