Coming to an idle problem

[green_drop]

When i rev up my car the rpms drop quick to 1500 and then slowly makes its way to an idle takes (5sec) I counted this is the most annoyning thing in the world and I thought it was my jacobs ignition box but it wasn't. I have no idea how to make it drop quick like it used to and how it does on all my other buddies mustangs.

 

[mo_dingo]

Have you played with the idle settings on the car???? What mods do you have?

If your idle settings are good, then my guess would be you IAC valve has a lot of buildup, and needs cleaning. Or, you will need a completely new one. If you don't know if the idle settings are good, you need to check. Do a search for "hanging idle". You will find out how.

I went through a fiasco w/ this sensor, so trust me on this. If you decide it's the problem and want to replace it, get it at Pep Boys. The autozone one did not work for me and someone else I know. Once they got the Pep Boys part, everything was well!
Scott

 

[HISSIN50]

does it do it always or just when coming to a stop light? if the latter, dont over look that a function of the VSS is to hold the idle at 1500 RPM or so, when moving.

have you checked for vac leaks? a leak can create a hanging idle (any speed). a stockish motor should pull 15-20" at idle.

good luck.

 

[green_drop]

it does it coming to a stop light which i understand that is fine. But when i am completely stopped and just rev up it still takes forever to come down

 

[HISSIN50]

pull codes, check for vac leak and clean IAC (amongst other things, but id do those first). my two cents.
good luck.

 

[GTJake]

New TPS fixed the hanging idle on my car.

Jake

 

[topdri]

I have an 89 mustang and I have replaced the tps, iac, maf, and coolant sensor - I still have an issue with a hanging idle. It jumps up to as high as 2200 RPMs. I turn the car off and that may fix it for a bit. I have my mechanic stumped now, of which is very hard to do.

Any ideas?