I have a 1989 f150 5.0 and the truck runs great. but every once in a while, like maybe twice a month or so. It will just start idling high. Jump up to 3 thousand rpm when I press the clutch in or put it in neutral. So my question is could it be a sensor sticking or something else? I have checked all of the idling cables and it all seems fine. If it helps it is a fuel injected engine . Thanks all the help I can get will b much appreciated.