1999 cummins, 157000 miles, auto, all stock except straight pipe. starts fine when cold. will not start after i shut it off when warm. will start though if i un plug the ECT sensor. truck runs perfect. 17-20 miles per gallon. has plenty of power for a stock truck. the only code that shows up on my scanner is the ECT sensor code only cuz i unplug it to start truck when warm. any ideas?