mustangspeedyGT

i have a 2000 mustang gt.. wen im just sitting in one spot the rmp's will drop to bout 600 and then raise back up to 2000 rpm's... the car has cut off like twice while just sitting in one spot... WAT would make the rpm's go up and down just sitting there and not touching the gas?? i just got a tune up on it and oil changed bout two weeks ago and didn't help any

Simon1

You need to post this in the section for your car.

The answer is most likely your Idle Air Control valave. It is connected to the thottle body and it is a very common thing for that particular car.

Google Idle Air Control, along with the year and model of your car and you will see some results. All you have to do is take it off, clean it and put it back on.

This may not be the solution for your car but it is very common.

2007VistaBlueGT

Idle air control valve is a good start. Next post in your own section perhaps it's a common service issue with SN-95s someone can help you with.

StickShifty

clean or get a new IAC, also clean out your MAF with MAF cleaner. that should do the trick.

07 GT/CS

Depending on how many miles you have on your spark plugs, they can cause sparatic idaling; example: my friends 1998 ford taurus. At idle sounded like crap with a bad idle RPM's would randomly jump, then the idle would steady out at around 1250 to 1500 RPM (normal idle is at around 750RPM, I changed the plugs and wired (had around 60,000 miles on that set) and whalla it's running like a charm....a charm wih an exhaust leak but running good all the same. Start with less expensive ans simpler things and work you way to the more dificult stuff. Ohh yeah and before the plug change the car would sputter alittle on initial acceleration and then smooth out at higher RPMs and would throw a code if he was driving like a bat out of H#^$, and when he calmed down his driving the code would clear. Hope this helps you out some.