Rotorhead

So lately my car has been starting fine, idles at 1k rpm for a few seconds and then revs up to 1.5k on its own. It doesn't happen everytime i start, doesn't seem to be affected by outside temperature or whether or not i was driving it recently. It idles perfectly right after that and the rest of the time i'm driving. It's just occasionally reving up to 1.5k immediately after starting it.

Any ideas?

Jon-1.8t

possible stuck throttle body... clean it

Silver Streakin'

normal. it's heating up the cat. RPMs should be ~800 and 1200, respectively.