[illinoisstang]

i have a 1994 v6 mustang.it has 119000 miles.5 speed,etc....already has the heads redone about 15000 miles ago.it runs and drives fine except for one thing.lately the rpms go up and down.when the car is sitting at idle it makes a click noise like a switch is going on or off and when it does this the rpms jump up for a few seconds.then it clicks and goes back down.its not a big deal sitting but its also doing it while driving.when moving in gear the rpms jump and the car accelerates.i dont know if its a sensor or what?i havent lost any fuel mileage or anything and the car runs great except for that.if anyone can help it would be greatly appreciated.thanks

[StalkerStang]

Sounds kind of like the A/C compressor cycling. Were you driving with it on?

I know my car runs totally different with the A/C on, idle stays elevated for a second longer or two when coming to stops and every time the A/c kicks on and off the rpm's raise for a bit.

Its all normal operation, however its supposed to be smoother and not as noticeable.

[illinoisstang]

nope....ac was and still is off.thats exactly what it sounds like but its doing it with the ac off and it does it while driving

[shinerstang]

Originally Posted by illinoisstang

nope....ac was and still is off.thats exactly what it sounds like but its doing it with the ac off and it does it while driving

If your defroster is on, your AC compressor will cycle......