I recently put a new block and heads in my truck. Ran great for about a month and then started to throttle up all by itself. went to about 1500 rpm then down. Did it while driving or in park. Have replaced the egr valve, the egr position sensor, the egr solenoid, the canister purge valve, the map sensor, the air idle control valve, and the throttle position sensor. now it only runs rough when cold. while cold it throttles up then drops and almost cuts off then back up and down. while doing this the check engine light will cut on and off and the throttle body will loudly suck air. once warm though it runs great. took it to a mechanic and they said that there was nothing wrong with it at all. Please help
Dec 3, 2008 at 4:17 PM