I disconnected the ESC connector on the pass side engine bay, set timing to 6 deg. I set IAC minimum idle by grounding AB on ALDL, waited 30 seconds, disconnected IAC connector. Started car, let it run for a bit, removed ground from AB ALDL, adjusted screw on back of TB and set the idle to 400rpm in drive. reconnected IAC and then reconnected ESC connector. Idled great at about 600 rpm. Shut off the car and when I start it it goes to 2000 rpm consistent. I haven't been able to figure this one out yet, any thought please. TPS is adjusted to .46 as well. It is a new (autozone) IAC and new GM TPS. Help!
Tony

 

I too am having somewhat the same problem. I ported my heads and put new cam in and now I am idleing at about 1800. I put a new iac in cause mine was a litle rough not the fix. I did notice when I disconect the tps while it is running idle drops to about 1000. Sorry I can't help but I will be checking in on the post to see what happens.

 

i think the correct way to adjust it is.

ground a-b aldl connector
turn ign on
wait 30 seconds
pull off iac connector/esc if need be
start car, adjust minimum idle
turn off car, remove a-b jumper
reconnect iac
then re start

 

Thats the process alright and mine is just like jstoll. If I disconnect the ESC it idles great and I can even reconnect it and it stays perfect but as soon as I turn the damn thing off and restart, 2000rpm again. Could the ESC be malfunctioning? and sending the wrong reading to the ECM. 86Z you know that just like Jstoll I have uped my cam and wonder if this is where the problem lies.? hummmmm

 

tps is supposed to be .54

 

oops typo meant it is set to .54

 

tony after you set minimum air try pulling the ecm fuse for 30 seconds, then start it and see if it idles high

 

Roger that, I will try it when I get home tonight.

 

I have noticed a few other symtoms with mine. I checked the tps and it read 2.5 at idle I even took it off the tb to make sure there was no issue there. It would slowly go to over 4 at wot but only drop back down to 2.5. I have a 91 with speed density do the tps is not adjustable. It is probably bad right. I did also notice that when I start my car is idles at about 1000 for a second or two then jumps up to 1800. I have put a new iac on already it seems to work. I could not find any vac leaks. I can kill the motor by putting a 2x4 over the tb. I can almost kill it by plugging the iac port on the tb. I am also getting a code 43. Not sure what that is.