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So here is the rundown. I come out of class and start my car to go home. I just notice that something isnt right, the normal vibrations and noise inst there. I look at the tach and the neon is idling at 500 rpm. I rev it up a little bit and it revs up fine then dies. Start the car again and its still idling at 500 rpm. Rev it up and it just goes back to 500 rpm this time without stalling. I drive home from school and at every stop light it idles at 500 rpm. There is no hesitation when I rev up and it goes to red line without missing a beat. No CEL is activated and no misfiring. Im completely stumped. Any ideas?

its an 01 MTX and the HVAC was all off when this happened.

Your IAC may be stuck, not opening. An open in the solenoid coil would set a CEL, but it not moving for a mechanical reason I don't think would. Normally when you key on it should open up, then once started it will stabilze the idle. Just remove the two screws and clean it with carb cleaner, and see if it is moving when the key is on. Usually it will sit there and make a weird humming noise with the key on, and engine off. If you key on with it unhooked from the electrical connector you will have a CEL.

Well I just went for a drive to the store to pick up stuff for work and when I pulled into the parking lot the idle finally went back to normal. Then on the way back home I slid it out of gear to coast to a red light then the RPM's hung at 3k. Then went to 2k then finally back to 1k for idle and this happened over a 10-15 second span.

Ill take a look at the ICA when I get home from work and see if thats malfunctioning.

IAC, TPS, MAP sensor, possibly your TB is dirty aswell. There is also a screw on the underside of the throttle cable where it connects at the TB. you can adjust that for the moment till you can test your sensors.

Just an update. It was the IAC. I cleaned it out and all is good!