My fuel system issue

[rfm77555]

99 expedition 5.4L ...parked while out running errands wont start for the trip home. I pull off one of the lines up near the intake, squirt in some fuel, it starts right up dies when the fuel is gone. When I turn the key I dont get the normal what I will call the 2-3 second fuel rail charge and I am certain the fuel pump is not running. After having it towed to the house I start checking things. The fuse for the fuel pump is good, the relay for the fuel pump is clicking when I turn the key to the run position, the inertia switch has not tripped. I drop the tank thinking I have a bad fuel pump and put on a new fuel filter while I'm down there. With pump assembly out of the tank I connect a 12 supply and ground from the cig lighter directly to the pump and she humms like normal. Put the pump assembly back together and with it out of the tank I turn the key and It works for about 2-3 seconds and stops dead. I go to the inertia switch and check with a volt meter the supply it shows only 6 volts. At this point I feel confident the problem is not my pump so I reassemble the whole thing and with the jumper from the cig lighter I splice into the feed out of the inertia to the pump. Turn the key and it starts right up and when i disconnect the jumper it keeps running. When I key off and try to restart I have the same issue no power to the fuel pump till I connect the 12 jumper. Whats up with my car????