02 Intrepid Stuck In Fast Idle

I have an 02 Intrepid manufactured in canada, purchased used from a dealer. I have had the car back to the dealer while under warranty for a fast idle problem. The problem is this: When the outside temp is 32 deg F or cooler, the engine remains in fast idle even after reaching normal operating temperature. Dealer technician can find nothing wrong. Chrysler tech support told technician to" check for loose connections". This sounds like chrysler doesn't have a clue as to why it stays in fast idle during cooler weather. It will go to normal idle after reaching normal operating temperature if the outside aur temp is above