So I pull through the drive through last nite and put the truck in park, and the RPM's jump to 1000 and then down to 400 and it smooths out and runs fine. Anyone ever seen this before? Its 4.7 2004. It drives perfectly fine and runs smooth just that enitial put in park second it runs wierd almost like it will rev and almost stall but doesn't. I am thinking its a throutle positioning sensor.