ok..the title says it all. It's really starting to bug me. My car sounds like I'm ready to tow a barge into port or something. It's only when it is cold outside and it starts making this crazy noise...rpms jump up in neutral then drop down. If I'm not in the car it typically will drop the rpms back down and then stall. Now if I'm in the car I can put it in gear and it stops. Once it gets warm it stops. So...any ideas?