1994.5 f250 xl. Truck intermitently stalls while driving and at idle. Usually turns right over and runs after. Sometimes takes 3 or 4 times to turn over but not often. If it stalls while im moving it fires up on its own after a few seconds. Some days the truck runs fine. Some days i think i wont make it home from work. Thought it was a fuel issue so i changed the fuel filter and cleaned the fpr screen. Problem continued. Any suggestions to what the problem might be?