Intermittent loss of Power
2003 7.3 powerstroke E550 box truck. Starts & runs fine but every once in a while after shutting it down & restarting it has no power. Won't even pull itself on the level. It doesn't stall and will idle but no power. If you shut it off and wait 5 or 10 minutes it will start fine and run good. May do this a couple a times a day or not at all. Pulled codes and shows nothing. Seems like fuel related. HPOP? Fuel Pump? Checked fuel for dirt & water. Drained fuel tank & nothing unusual. Any ideas?