Repost...idle problems

jermy82

jermy82

Founding Member
Feb 2, 2002
446
0
0
Sherman, Illinois
#1
Posted up a couple of days ago and got no responses. Hoping to get a couple this time.... Problem is that the stang won't idle right. In park and neutral it's fine, but in reverse or drive it won't stay still, just goes up and down and sometimes dies. I took off the battery for about a half hour with the door open to see if the computer just needed to be reset cause I just put a 65mm TB on, and that took care of the check engine light that had been coming on I think, but I've only driven it one time so... Anyway, tried to adjust the idle...turned it up too much and the car kinda surged a little while I was driving so I turned it back down. I read around a little bit and think it might be the IAC, cause that controls the idle when the car is just sitting, but that's my best guess. The only thing is that wouldn't the idle be bad in park and neutral too?...and if that's bad, why was it running fine before the swap? Really could use some help cause this is getting a little frustrating. Thanks.
 

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#2
i think there was probably another thread going on at the same time about the same problem. In there they discussed readjusting the IAC and i'll see if i can find the post/faq about how to do that. My best (not very educated) guess would be that the throttle cable is not installed correctly to the new TB or is hanging up on something. I'd check on that as one of the first things
 
#5
I just got done adjusting my idle..... Pain in the a##!!! :bang: :bang: but it is finally idleing pretty good. Try this but don't forget once you connect the IAC and blip the throttle a few times it sets the computer, so any major adjustment after that will make it worse. The trick is to get it ideling with the IAC disconnected then connect the IAC. You will need to disconnect the POS term of the batt. for a few minutes to reset and start over. It took me like 8 resets to get it perfect.
Good luck... :nice:


The recommendation is key on, engine off, (KOEO) 0.995-.998 D.C. High TPS voltages are characterized by a very erratic idle or stalling when coming to a stop (ECM error code 66).
Set the throttle by removing the connector from the Idle Speed Control Motor, with the engine warm (and the air conditioner off). Using the throttle screw set the Idle Speed at 700 RPM (or desired RPM). On '94 and later models use the idle bypass screw. The screw is located at the right side of the throttle body, covered with a plastic cap. Reset the TPS to obtain 0.995-.998 volts D.C. between the black and green wires on the throttle pot. If the unit has no voltage, check the voltage between the black and orange wires. This should be 4.9-5.1 volts D.C. with the ignition on. If the voltage is 4.9-5.1 D.C. and there is no voltage on the green wire, the throttle position sensor is no good. If there is no voltage on the orange wire, you must find a break in the wire. Reconnect the Idle Speed Control Motor and check for engine stability. :banana: :banana:
 
#7
Your check engine light was on for a reason!!!!!! You should have checked the codes. It would have told you where to look.

Reconnect the battery, and drive for at least 10 miles. Hopefully the CEL will come on and trip a code. After driving for said distance, check the codes anyway.
Scott
 
#8
Same problem while idling

I have a 94 gt auto. and i have the same problem. I have had a lot of people tell me a lot of different things. I cleaned out the throttle body, there was a lot of gunk in it. Then i replaced my IAC. That didnt do anygood for me but after reading this i was wondering what the procedure was for replacing my IAC. I just unbolted and then bolted up and plugged in the new one. Can someone tell me how exactly to do it and what i can do to correct this problem?
 
#9
mo_dingo said:
Your check engine light was on for a reason!!!!!! You should have checked the codes. It would have told you where to look.

Reconnect the battery, and drive for at least 10 miles. Hopefully the CEL will come on and trip a code. After driving for said distance, check the codes anyway.
Scott
Click to expand...

This may sound stupid, but I really don't know how to check the codes. Can you tell me exactly how to do that? Thanks everybody so far...this is the first time I've checked the post for a day or so...been busy as hell, but I'll post up what happens as soon as I get time.
 
#11
White94GT said:
i just had an idle problem with mine too, i went through the steps on this site and it fixed my problems

http://www.muscularmustangs.com/iac.html

hope this helps
Click to expand...

Okay, tried this out and it idled fine for one "test." After that it's doing the same thing. But before I try anything else, I noticed that the plug that plugs into the IAC has a plastic red piece on the inside of it that seems to just slide out now and seems to be broken. It stays in there when plugged in of course, but I was wondering if you could buy another one of these somewhere....
 
#12
jermy82 said:
This may sound stupid, but I really don't know how to check the codes. Can you tell me exactly how to do that? Thanks everybody so far...this is the first time I've checked the post for a day or so...been busy as hell, but I'll post up what happens as soon as I get time.
Click to expand...

Don't feel bad. Everyone has to learn. First thing, get a haynes/chilton manual. It will tell you the exact procedure for checking the codes. All you need is a jumper wire to get the CEL light to start spitting out the codes, but you need the haynes manual to understand what is going on.

Once you have the codes, use this as a explaination chart. It also tells you where to put the jumper wire. Don't waste the money on a code scanner, BTW.

http://forums.stangnet.com/showthread.php?t=479678

The red thing inbetween the two wires is a wire seperator. That is it's only purpose. Hopefully it will not break and cause problems. If not, return your new IAC and get a new one. Might as well since it's easy to replace and free.

Scott
 
#14
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