Ok first off my truck got stuck in 4WD and refused to come out even when the switch was moved back to 2WD. Then I now have a recent problem with the engine rev. When the truck is idling like at a traffic light or just when its started and throttling the revs are very irregular. It behaves like its not getting enough fuel and like it wants to shut off. In fact in has shutt of on quit a few occasions. It also will just rev very high and then go below 800rpms. Any ideas??????????