Idle drops to 400-500 when stopping.

[Wi-Stanger]

What could my problem be here? When I come to a stop the RPM's drop to 400-500 about half the time and then after about a second or 2 the idle goes back to normal. I just changed the IAC and it still did it. What else could there be?

Thanks for any info.

 

[bdcardinal]

when you changed the IAC did you clean out the ports that go into the plenum? i had the same problem and cleaned it out and the problem went away.

 

[Get E Up 98]

I had this same problem not to long ago and it was a combination of injectors/plugs... but I dont know exactly what your car is doing...does it hesitate or sound like it wants to shut off?

 

[Get E Up 98]

I also had this problem when one of my O2 sensors went bad...near the convertors

 

[StratGT]

What could my problem be here? When I come to a stop the RPM's drop to 400-500 about half the time and then after about a second or 2 the idle goes back to normal. I just changed the IAC and it still did it. What else could there be?

Thanks for any info.

My car did that when I dropped in a K&N filter, I unhooked the battery to reset the computer too. Then I replaced the K&N with the stock filter and the idle returned to normal.

 

[Gunfighter]

how long have you had the idle drop? The same thing happend to me when i removed the air silencer and added a K&N drop in filter. After about a week of regular daily driving, it returned to normal idling functions.

 

[mto gt2000]

I have the same problem, my car drops to 400/500 every once in a while after warming up. It doesnt bother me but it would be nice if it went away. I had the battery off and it didnt go back to normal.

 

[ghoststripes]

I have a stock 2000 GT and it happens to me too, usually when its either just warmed up or before getting warmed up. this GT is stock, what could be the problem?

 

[stangman16]

My '99 GT does this same thing, but when I have the A/C on, it drops to 300 rpms or so. Someone told me to have my freon recharged and it should go away.... i'm not sure when I'm going to get to check it out or not. I've so far cleaned the TPS, changed my IAC valve, and no resolve.

I know alot ford haters, go figure, and so they like to point out the flaws of ford to me all the time. I remember them telling me once about the A/C compressors crapping out ealry on fords... I dunno if thats true or not, but it uses the belt, and it made my rpms drop worse with the A/C on. Could it be a compressor issue maybe? I dunno, i'm just throwing bones at this point - this issue with my car is really irritating me once I come to a complete stop.

 

[ghoststripes]

This happens to me and I NEVER use the AC. BTW you said you cleaned the IAC valve? what is that?