okay so i have a 2000 Trans am m6 that is completely bone stock. today after driving for a while i parked it then came back out like 45 minutes later. when i started it, it idled at like 300rpm so i gave it some gas and it kept droping to 300. i backed out of the parking spot then drove it forward like 20 feet. when i let off the out the clutch in neutral it idled at 350 again until i came to a complete stop. once i stopped the idle moved up to about 600rpms. each time after that i gave it a little gas itwould drop to 300 and then go up to 600. so i drove it around the block and it drove fine but everytime i would let out the clutch in neutral it would drop down to 300 until i came to a complete stop and it would jump back up to 600. so idk why its doing this but any advice or info would be very helpful. Thanks

 

Sounds like a bad IAC valve.