i had this problem just last monday on the way back from school. The throttle body is gummed up and needs to be cleaned. Take the throttle body out carefully take the screws out of the flap(they are flared out on the other side to keep them from coming out but will come out and go in fine, its kinda wierd but you will know what im talking about when you see it), next take off the c clip under the throttle postion sensor.Next slide the shaft out. Now just clean it all real good with some carb cleaner , and just put a little lithium grease on the bushings when you put it back together.