I have an 04 sierra that will shut it self off if not let run for a while before i drive it.. If i dont let it run, while driving if i let off of the gas to slow down or to come to a stop my truck will shut off.. unless i give it gas to keep moving, and other times it doesnt die the rpms will bounce up and down pretty quick, or the rpms drop EXTREMLY low and just stay there for a second (while stopped) then go back to normal. As long as my foot is on the gas there isnt a problem. Any help would be great thanks