AH gremlins in the 6.0 I have a 06 f350. Try to avoid having the dealer throw a bunch of parts at it.... it will cost you a fortune. Before someone disconects the batteries, see if there are any codes stored in the computer. Not all codes will set a CEL. As said have each of the batteries load tested,disconnect all the battery terminals and have someone with a load tester or hydrometer check the batteries. Do the cheap stuff first,,,,, change the fuel filters,I don't know if there is a pump in the tank but make sure it is pumping at the required rate, There is lots of stuff that could cause this,bad fuel, bad filters, low voltage on FICM,bad starter,,,, the list could go on and on. Good luck and let us know the final outcome.