I cleaned the IAC, and now it's idleing wierd.

[_jb_]

I cleaned my IAC two days ago, and it was dirtier than a whore on nickle night. After I cleaned it, I put it on the car and started it, and now it will idle at about 1500, and about 5 mins. later it drops to the previous idle (750ish). So then, I reset the computer, but that didn't change anything. I've turned down the idle on the throttle body, but that doesn't solve the problem.

After the car starts to idle correctly, I would turn it off and restart it, and it would idle fine. Yesterday I worked 7 hours, and when I went and started my car it jumped up to 1500 again. Today, when I stated up the car after work it was about 1000, and then when I got home it was still at 1000 in the garage. When I got a screwdriver to mess around with the idle screw on the TB, but then it started to idle correctly.

The car ran good before I messed with the IAC. I figured since it was 109k miles on it, no one cleaned the IAC. Any ideas on what has happened?

 

[The Shape]

Sounds like the plunger is still sticking. Also was the gasket still in good shape?

 

[90mustangGT]

A new gasket would have been a good idea. I would make sure the TPS is set to .99 and then disconnect the battery for a while so the computer can relearn.

 

[_jb_]

Sounds like the plunger is still sticking. Also was the gasket still in good shape?

The gasket wasn't in good shape, dired up. Looks like it is the one that has been on the car forever. How do I unstick the plunger, buy buying a new IAC? How much do they run?

 

[_jb_]

A new gasket would have been a good idea. I would make sure the TPS is set to .99 and then disconnect the battery for a while so the computer can relearn.

After I started up the car and it was running at 1500, I tired checking the TPS. How am I supposed to turn it? I loosended the bolts, and I read that I am supposed to be able to turn it, but do I turn the whole senor?

 

[The Shape]

They run around 50-60 bucks I think. You can buy just the gasket from 50resto and probably can pick one up at the dealership as well. As for as unsticking it I normally just clean mine with throttle body cleaner and a Q-tip. I would unhook the battery first like 90mustangGT said and then drive it and see if the computer fixes it itself. As far as the TPS I have never been able to tell any difference unless the sensor just has a dead spot in it. Last time I had to replace one I just put it on in the parts store parking lot and it has been fine ever since. You can do a search on how to adjust it if you won't , but I am not convinced it "really" affects anything by adjusting it.

 

[_jb_]

I did leave the battery disconnected for like an hour when I reconnected the IAC. When it was running at 1500, I was like, "Well I guess I'll reset the computer as well".

When I reset the computer, I followed http://www.muscularmustangs.com/maintain.html . I couldn't get the car to start without turning up the stop screw in the TB a little.

 

[mustangsquared]

To make the TPS adjustable you have to elongate the holes...with a drill or dremel. Not too much as you only need a little play in it.

 

[_jb_]

I'll probily get a new IAC today...if my car doesn't start acting right.

 

[_jb_]

Replaced the IAC, works fine now.

 

[Zrated383]

Replaced the IAC, works fine now.

Mine was giving me the same problems so I bought a new IAC and after resetting the computer and all that other stuff it still would jump from 900-1500. So I just disconnected the IAC and it runs great.

 

[_jb_]

Now my throttle doesn't seem to come down as fast. WTF? I reset the computer and it still does it. If I just give it some gas it will return to idle speed well. While when I'm driving and I push in the clutch or even pop it out of gear it go down about 200RPM, stay there for a second or two, then go to idle speed.