frdmstng1986GT

well i got a new mustang finally. ( https://mustangforums.com/forum/5-0l...he-saddle.html )

The problem i'm having is that it wont idle under 2000 rpm with the iac plugged in. i did the base idle reset on it and with the iac unplugged it idles at like 750-800 rpm. plug the iac back in and it wont idle under 2000rpm. am i correct in thinking the iac is bad? i have already cleaned it. cleaned maf. checked and set tps. looked for vacum leaks and fixed the ones i did find and still no change in idle with iac plugged in.

Also, if it is bad, will the iac off my 86 bolt on and work?

Thanks in advance guys, feels GREAT to be back. i forgot how much i missed my mustang till now. lol

Bobert

When you did the base idle test was 750rpm the lowest you could get the idle when you adjusted the t/b screw?

When unscrewing mine i can stall the car because i can lower the idle so much.

Unplug the iac and see if you can lower that idle with the screw.

frdmstng1986GT

no. had it all the way backed out and it would stall if i let off the gas. i adjusted it to 750 rpm and left it there with the iac unplugged. shut off car and waited 2 mins or so then pluged iac back in and it wont go below 2000 rpm. my guess is bad iac.

883109

wierd, whats everyone idle @?

nightmare90gt

do you have a cam or anything done to your car, my guess is try cleaning the iac and see what happens and if it is bad get the motorcraft one

frdmstng1986GT

no cam i dont think. it idles pretty smooth at about 750 to 800 rpm with the iac unplugged to have a cam i think. im almost sure that the iac is bad but was just trying to get some other opions. i have already cleaned it twice just to make sure it was clean, plus done every othere idle fix procedure out there.

im pretty sure they are the same but does anybody know if the iac off my 86's motor are the same for sure? everywhere i look list 86-93 for fitment, just want to be sure before i rob it off the motor.

1ATony

They're the same from 86-93. We carry them here. Here's a link to them if you would like to check on pricing.

All of our parts have free shipping on them.

Mustang IAC Control Valve

frdmstng1986GT

thanks for the offer man, but money is a little tight and i got a good working one on my 86 motor that i'm gonna rob it off of. Thank you anyways.

soon2bu

I don't have much knowledge of this, although when searching for idling issues of my own, I came across the general consensus that IACs don't go bad. Or they rarely go bad. Like others said, I would clean it out, and go from there.

I cleaned mine out, and it wasn't much better, although others have had it help them.

mustangbuilder26

my 87 is doin the same thing but im not even sure how to start with checking the iac on it but from wat im reading here it looks to me like if i unplug mine i can adjust the idle with it unplugged and set it around 750-800 rpm am i folowing this correctly ?