87 T TOP GT302

I'm having an issue with my Mustang idling. After it get to operating temperature the idle will go to 1300 rpm's and stay for roughly 20 seconds. After that it drops to 1000,which is what I got the idle set at. It will stay at the 1000 rpm's for may 5 seconds then back up to 1300 . I have put a new idle air control valve a couple years ago.
Also the car is driven very little maybe 300 miles a year .

64bit

set your idle RPM back down where it belongs... It's too high.

88 orangepeel notch

And update the last sentence in your sig. lol

Seriously though, "Base Idle Reset" is what I'd do first.

87 T TOP GT302

Problem fixed.Had idle adjustment plate, fits between idle air control and throttle body removed and reset idle . Back to normal now idling at 900 rpm's.

88 orangepeel notch

Glad to hear, congrats.

64bit

still idling too high though