Just removed the front fuel tank on my '88 F-150. It was leaking. Plugged the lines going to the selector valve. Seemed to work fine for the next 100 miles or so, then it just quit. Driving down the road, and the engine just stopped. Cranked normally, but just didn't want to start except a few sputters with full throttle. Towed it to the nearest farm and left it for the night. Next day, it starts right off and then quit 100 yards out of the driveway. No warning, just quit. We towed it back again and did some basic troubleshooting. There is spark. Pulled the fuel line off of the output end of the fuel filter that is strapped to the frame more or less in front of the driver's left foot. Turned the key to run, and then to start. Not even a drop of fuel. There are 14 miles on this tank of fuel and the gauge still reads full. I'm thinking in-tank fuel pump or clogged filter. Seems unlikely that the filter would just clog solid with no warning. When the key is first turned on, I can hear a whirring under the hood.

Here's where I need help.

As I understand it, there is a pump there that runs for 5 or 10 seconds on start up, but that's in the system after the filter hung on the frame. Does the in-tank pump run all the time, or only after the engine is running?

Please educate me on these pumps and any other ideas you might have. Is there anything wrong with simply plugging the hoses that used to go to the front tank? Seems a strange coincidence that I should develop fuel system problems after removing a tank.

Thank You
Craig