doobs

My car has currently been falling down below idle to 500 or so rpms when pushing the clutch in. It even gets down to 250-300 and i've had the car stall once from pushing my foot in on the clutch and the rpms dropping. Any one else had a similar problem like this? Any input would be great.

P.S. I do have a tuner and have reinstalled tunes to see if the problem could be fixed.

Hufenstang

kinda weird... i was just about to post about this. Mine started doing this couple days ago. Only when the A/C is on and the clutch is in or if im idle.. I have no idea whats up with it =(

AmericanSpeed

When I had installed a lighter flywheel, I was getting an erradic idle that would go high and then drop down to almost stalling. I adjusted the idle with my tuner up 40 rpm which is one click of the sct. You may want to try that, shouldn't hurt the car to be idling around 800 rpm or so.

sactown

I just noticed mine does the exact same thing with the AC on, probaly just need to kick the idle up a little.

doobs

I tried adjusting my idle rpm and driving rpm, but no luck with my problem of the car dropping down to 250 rpms every time I push my foot in the clutch. I took off my intake and wiped everything down and made sure my maf sensor was clean and no luck. what do you guys think could be the problem?

Hufenstang

Does your idle rise and fall over and over again? Does your 'Stang stall when you come to a stop, or even when you put it in gear? Well if so then this series of articles if for you.
In this age of fuel injection, idle problems can literally be caused by hundreds of different things. What this series of articles is aimed at is how to fix the most common idle problems found in the Mustang.
The fuel injected Mustang uses a small motor/valve assembly that allows a specific amount of air to enter the engine to control it's idle. This valve is comonly called the idle motor, the IAC (idle air control) or the IAB (Idle air bypass). When your car is new the IAC works remarkably well. The problem arises when the car gets some miles on it (usually 75K+) and carbon fouling takes its toll.
What happens is dirt, excess air filter oil, and most notably carbon gunks up the IAC valve and doesn't allow it to either open or close properly. This can cause an really high idle, a lumpy/surging idle or no idle at all. The solution is to either replace or clean the IAC.

A ford tech also told me about this so im going to try it since my car has 90k miles anyways. IAC is idle air control valve

blike

I had the same problem - cleaned out my throttle body and my idle was smooth as butter

doobs

what am I going to need to take off the IAC? Is it just two bolts and a gasket that I have to worry about to take it off and put it back on?

Hufenstang

i really dont know where it is located, im trying to figure that out right now myself. I know that you can tune the iac with a tuner but im not sure how that works either..

thewarmachine

My idle would plummet when I had left the vacuum hose disconnected from my CAI hose. I reattached it, and everything was fine.