99 neon High RPM's

My neon starts up at 1800 RPM's and stays there. When the AC is turned on, it jumps to 3000 rpm's untill the compressor shuts off. This started a few days ago and used to run around 1200 RPM's. Any ideas?
Thanks
Dave

I had a similar experience a couple months ago, it turned out to be the TPS (throttle position sensor).