2004 Gt, Sometimes when I pull up to a light the Idle hangs around 1500 rpm, Sometimes the rpms goes up and down then just about shuts off then back up if I keep my foot on the gas it is ok, if I go out and start it now it will idle for about a min then shut off

Any Ideas, I took the IAC off and cleaned it with throttle body cleaner it's only $117.00 might just put a new one on, I just hate trial and error troubleshooting

 

I actually had this happen one time in my driveway. I fired the engine, and the motor idled, then the rpms went way dow and the lights dimmed. Then it seemed to recover for about 10 seconds, then it happened again. I shut it down and restarted it, and it was fine. Havent had the problem since.

I know this doesnt help you at all, but i've had a similar experience

 

chances are it is IAC related, how may miles on the car and when was the last time you changed your PCV valve? also of note, $117.00 is a little high for and IAC, even an oem Ford one.....if you find you do want one, we're only @$70.00 for an OEM one wth gasket + s&h

 

i had a similar problem awhile back.

check your pcv valve elbow hose. it's right underneath the air intake as it connects to the throttle body plenum. take it off, and manually inspect it for cracks, slits, cuts, holes. this will cause the problems you're having as well.

also make sure the clamps on the both sides of your maf air sensor are tightened down.

if that fails, replace the IAC.