Idle stuck at ~2k rpms and can't fix it, help!

Milky

New Member
Dec 17, 2003
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I installed a new IAC to get rid of a broken plunger, reset the computer, installed it and had the idle to low. I upped the idle with the idle screw exactly where i wanted it and it was fine but I didn't let the car idle long enough for it to "learn" the new idle. When I started driving it the idle then stuck at 2k rpms and for life of me I can't get it down... I reset the computer several times and unplugged the IAC several times and nothing will help....

Can someone tell me how to truely reset the computer and teach the computer its idle??? Ive got a 94 cobra J$14 computer if that helps...
ANY help is appreciated...
 
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I don't think its the tps it wasn't touched and was set fine before... How is it possible to tune for better mileage btw ( I read your sig) the more air the more fuel you need to even the mixture how do you get around that?
 
Now I am indeed confused. Took off the negative cable for over 2 hours, with the IAC cable off as well and the car STILL idles at ~2k rpms... It can't take more than that to reset the computer can it? What else can I do?
 
Take off the IAC motor and make sure it's not stickin' dood. That is the most logical thing to do. Just becuase the part is "new", doesn't mean it works! Believe me, I've bought new parts that are broken out of the box. Just make sure it's good. Another thing you can do it put your old IAC in (as long as it wasn't having the same problem) to see if that's your problem.

Nick
 
Also, I put the new IAC in the exact way the old on came off dspite a really crappy diagram that came with the new one saying it had to be put on the opposite... but I don't think thats the problem...
 
Swapped out to another IAC, same problem, tested plunger it works fine... don't know why it still sticks at 2000 rpms and i don't want to drive the car until its fixed...
 
ok, check for vacuum leaks! Best way to do this is get some carb cleaner or throttle body cleaner and spray it around you engine bay, around vac hoses.. Around the intake to head area... If they car revs up, you got a vac leak. Another thing to do is unplug the IAC and see if it idles down. If it does, it's something to do with the IAC or the wiring. If not, it's gotta be a vac leak.

Nick
 
OK, So you replaced the IAC and reset the computer. Started the car and the idle was too low, so you increased the idle using the throttle plate stop screw. Now its idling too fast. Forgive me if I missed something, but why can't you just turn the TPSS back out?
 
The TPS was never touched... Evertime I go to reset the computer and unplug the IAC, the idle still stays to high, so... resetting the computer and attemtping to set a new idle does not work in my case.
 
Milky said:
I unplug the IACV and the idle still stays high and there are no vacuum leaks, I have double and triple checked... :bang:

You have either a mechanical problem like binding throttle linkage, sticky throttle body or a vacuum leak. Double check the small hoses where they connect. This is the most common place for leaks.

No vacuum leaks & no sticking mechanical components, turn the idle speed screw down. Remember to adjust the TPS voltage anytime you adjust the idle speed screw.
 
Hey guys,
I'm interested in the results too. I just installed a 75mmBBK throttle body and the idle is slow to return to 700. It wants to stay above 1000. I'm hoping that the posts I've read help.
 
If its what I think it is, its just your computer. As you coast it stays at about 1k until you stop, then after about 2 or 3 seconds it idles again... if its kinda like that Ive experienced that with all 94-95 stangs ive been in.