MY 1989 VAN IDLES REALLY HIGH I REPLACED THE THROTTLE POSITION SENSOR AND THE IDLE AIR CONTROLL VALVE STILL DIDNT HELP.ANY IDEAS WHAT ELSE WOULD CAUSE THIS THANKS
A couple of things come to mind. I would check for any type of vacuum leak first, then make sure the throttle is closing all the way. There should also be an idle speed setscrew on this truck, so it could be as simple as that.