MYSTIC-1SC

iTrader: (14)

How much can a bad iac motor effect performance, and how can you tell if one is bad? I have a 2000 z28 with the mods in my sig and when you rev the car in park or neutral it sometimes is slow to return to idle. I was curious if this was all in the tune or the iac motor could be bad or you guys could send me in the right direction as far as figuring out what is causing this. Also when i do a burnout or blip the throttle real quick it has trouble getting the idle figured back out and wants to die sometimes and fall below idle. Let me know what you guys think.
thanks.

W es 6

iTrader: (1)

I still have almost your same problem... I replaced my IAC valve and my TPS to no avail, hopefully we can figure something out here...

MYSTIC-1SC

iTrader: (14)

yea im hoping points us in the right direction.

runtwrestlin

iTrader: (3)

I too have basically the same problem, but it's not too terrible once I've driven the car a few times. If I unplug the battery for a while and then drive it, man does it have a rough time finding the idle. Maybe the PCM relearns the fuel trims to compensate or something; that's just my uneducated opinion.
I've been told that I have an air leak (???), but replaced the intake gaskets and checked all the vaccum lines to no avail. However, in a lil over 2 weeks I'll be getting my rebate back from college (Thank God for scholarships), and I'll be getting the LS6 intake. I mean, I don't really see how the intake could be bad, but I dunno. Can't hurt to upgrade Hopefully y'all will have some responses more knowledgable than mine before then.

MYSTIC-1SC

iTrader: (14)

Yea it is definetly an annoying thing hopefully we can figure something out to cure this issue.

Hi-Po

iTrader: (4)

You need to hook up HPT and see what the AIC counts are. They should be 45-60ish at hot idle. By adjusting the screw on the TB, you can help the AIC gain some counts. But HPT is going to be your friend if your wanting to find AIC problems.

MYSTIC-1SC

iTrader: (14)

thanks for the advice. any body else have any tips.

runtwrestlin

iTrader: (3)

Soo... I did as Hi-Po said and scanned the car while driving... When I 1st turned her on and the ECT was ~160 the IAC Position was ~35. When the ECT ~195, the IAC Position at idle would dip down to 8, then back up to ~35, and after driving for a lil while it would pretty much be around 0 when at idle...
When I turn the AC on the IAC Position jumped up to around 70, but then settled around 35.

I'm not sure what to make of it, other than it clearly shows something is wrong if it's sposed to be between 45-60. I took the IAC Valve out of the throttle body and cleaned a decent amount of black deposits off of it, but that didn't seem to make a difference.

I attached my HP Tuners scan. If I need to scan again with different parameters, or anything like that, plz let me know. Any help is appreciated!

PS It's a 98 LS1, stock except for the few mods in the sig