Revving when clutch in

My 96 Saturn SL1 is revving when I clutch in. Normally high idle of about 1000rpm anyways but whenever I clutch in it jumps to 2500rpm, when I go back to the accelerator it instantly goes back to where it should. But when I come to a stop it will hover around 2000rpm before slowly going back down to a rough 1000rpm. This problem is only 2 weeks old and since it started happening I have had my fuel lines cleaned, my oil changed and I put a new starter in. (Not because of the problem) The car also seems to be trying to hold its speed, so if I am going 50 it seems to want to maintain that speed almost like the cruise control is interfering even when off, which was my original thought. Any ideas???

Replace your Engine Coolant Temperature sensor

Clean your throttle body mainly your Idle Air Control Valve and its passages. This valve is sticking along with getting bad signals from the ECTS.

Pretty clairvoyant their my friend, I forgot to mention that my coolant gauge stopped working as well...hmm, how expensive are these fixes and can i do them myself?

Your temp gauge is connected to the ECTS.

ECTS is 20 bucks at the dealer, 8 at autozone etc. You will need Teflon tape if you get the autozone one. You will also need a 13mm deep dish socket and ratchet. Do not over tighten the new sensor, just make it snug. Check the connector for corrosion. If there is any replace the connecter (30 bucks at dealer, 5 bucks at junk yard)

Clean the TB with brake cleaner or carb cleaner and a rag.

Over all should take 30-45 min, if that.