I have a 1999 F-800 with a 24V Cummins. 166Kmi with an Allison auto. While driving the truck today it stalled in the local Lowes parking lot and wouldn't restart. It have about an 8th of a tank so I figure it was below the pick up. I waited a couple minutes and tried again and it ran for about 20 second (enough to get me out of the way of the loading area and stalled again. I walked to the gas station and got 5gal of diesel. It started again and stalled so I opened the top of the fuel filter and turned the key on...no fuel, so I figured it was the lift pump. I replaced the pump with a new Napa unit and again it fired right up and stalled just like you shut the key off. Pulled the top off the filter housing and no fuel when the key is on. Next I hotwired the lift pump and it fired right up and ran long enough for me to think I fixed it and then stalled. if I wait about a minute, then it will start but only run for about 30 seconds before it shuts off regardless of whether the lift pump if hotwired(running constantly) or not. The engine warning light is not on. Any ideas?