well, this may be minor, but i'd like to know what caused it. last night i get home and put the car in park. i notice that it's idling at 1500rpm, where it's normally ~800rpms at idle. i try to rev it to see if it would kick down. no go. try putting it back into gear and it engages firmly and goes to 1000rpms. put it in neutral, rev it up to 4000 and it still goes back to 1500. so i put it in park and shut it off. waited about 15 seconds, and fired it back up. it was now idling at 800rpm where it normally does. no problems since. any ideas? isolated incident?