check the most basic stuff first before going to a shop to have em diagnose it. Check the FITV. The fast idle thermo valve controlls the car's idle (i'm only guessing as it can take 10-15 minutes to warm up, if you drive ligjhtly and its freezing out.) Have the distributor checked for the contacts (the cap and rotor can be checked by removing the cap's phillips headed screws. could also be the plugs or injectors, so feel free to add some dry gas to the fuel, if the car is either higher in mileage or has sat for any extended period of time.