[BULLWHIP1]

hello
my 1992 mustang 5.0 GT has a idle surge up to 1200 rpm , it will do this after idling at 750 rpm for a good 30-40 minutes, then out of the clear blue it will jump to 1200rpm and stay there, but if i shut the engine off and restart it right away it will go back to 750 rpm, i have changed the IACV, and cleaned the throttle body with throttle body cleaner ! any ideas ?
thanks

[EagleAutosports]

Start by checking all the codes and go from there. Something isn't functioning properly and hopefully it'll throw a code to help find it.

[coolwaterblvd]

Check all of your vacuum lines esp the ones under the intake, in the front it is a oppy size hose end, and splits the hose easily. Also clean your MAF meter with MAF cleaner. When u know all the lines are good. Pull the batt cable off for a few min, crank the car let it run for 2 min then rev it up to 2000k for 2 more min this fixed my car. This is a little old school info I learned from a ford tech. This truly reboots the car's computer this is different than just pulling the batt cable off.

[BULLWHIP1]

thanks, and i will try that !!

[BULLWHIP1]

thanks coolwaterblvd i did what you said and it worked !!!!!!