I have a 2003 FX-4 "Flareside" 4x4 with the 5.4 v-8. It has started shutting off when the engine is at idle. It will crank back up, but when you put it in gear it lunges forward and shuts off again, after multiple attemps, it will stay in gear and drive correctly. Any idea what the problem could be??? Code reader shows no error codes.