Mine does it too, but I have a head gasket leak and that may be a big reason. I had done all the things mentioned above and I still had the problem. Although, running SeaFoam through the system gave great results and showed that it has to do with the intake system and the injectors as well as the head gasket leak.
1) Run the SeaFoam through the system as suggested and see if that helps. If it does, have the injectors cleaned or replaced. If they are cracked, they will cause these same problems.
2) Check the motor mounts. If they are worn (and they will over time) the engine will seem like its idling poorly when its cold, but then again, the engine will do it when it’s hot as well but not all the time.
Try the SeaFoam.
On the other hand, you could have a head gasket leak and not know it. It may be small enough that when the engine is cold, the area in question is opened more causing a leak and rough idle. When the engine gets hot, the engine and heads swell enough to close off the gap and idles fine. Even though my car idles fine when its hot, I smell coolant and have less power than years ago. So ya, I'm doing the heads in a couple weeks. Any suggestions are welcome on how to change out the heads.
Last edited by white lincoln; 03-16-2007 at 04:30 PM.