99 Idling Problem

Hello all, I've got a '99 GT 5-speed that I bought in 2001. I've pretty much only done cosmetic work to it, and have had no problems with it mechanically. Two weeks ago, it was very very cold (below freezing) for a couple of days. I went to start it up, and it turned over, but the idle went straight down and the car stalled. I got the car running by giving it gas right when it started, and it was rough for a second, but then I easily held the idle manually via the gas pedal like normal. Once I let my car off the pedal, the car stalled. I went back the next day with some dry gas, and manually idled the car again for 10 minutes. The problem still persisted. I decided to just drive it and open it up. I couldn't even get the car into 1st gear after going into reverse. However, when I started the car, it worked normally all of a sudden.

I was wondering if anyone had any ideas,

Thanks.

Reply to
Brian C
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check the iac valve, search for it online, but it should be the black valve looking thing on the throttle body facing forward.

the iac valve, or idle air control valve, does what it is called, and controls the amount of air into the engine at idle. my auto 99 had this idling problem as well, and all you need to do is to get a can of carb cleaner, and take the iac valve off, and spray inside the iac valve to remove any carbon deposits, because the carbon deposits are holding the valve portion closed, thus not allowing your mustang to idle. sometimes it releases, as you said when it worked "normally all of a sudden"...

Reply to
ssj4.gogeta

I'll give it a shot thanks!

Reply to
Brian C

Idle air control valve. Remove it, clean it with throttle body cleaner. Safer for the rest of the intake than carb cleaner. Just in case you don't get all of it out. I had the same problem, first time it went away on it's own and didn't reoccur for a couple years. The next time I cleaned the IAC valve real good and it's been fine since.

Reply to
Brent P

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