'84 F250 fuel pump?

My 84 F250 (460ci) is getting fuel while the starter is engaged, but after it starts I lose fuel pressure. I don't know if the fuel is pumped by vacuum once it starts or if the pump should keep pressure. I have duel tanks.
Any advice would be greatly appreciated, especially if it's a cheap fix LOL.
Thanks,
Booner36

is there fuel in both tanks?? sometimes the the tank selector screws up of the wires break. i believe your motor has a mechanical fuel pump on the side of the block. follow the fuel line from the carb. sometimes the diaphram goes bad in the pump. replace your fuel filter too. i've seen a few old trucks where the fuel pump bolts loosen up and the cam can't fully pulse the pump. good luck

Yup, gas in both tanks. Elect fuel pump(s). They are pumping while the starter is turning but they stop after the truck starts. It runs until the fuel in the carb runs out.
Could this be a bad ignition switch? I get no warning lights when I switch the key on. Maybe a bad relay somewhere? I did find a safety switch that shuts off the fuel pump in the event of a crash, I reset it with no improvement.

i think you might have to get a book with a wiring diagram. i'm not sure what the circuit looks like for an 84. new fords need to see a tach pulse to power up the pump. a haynes or chilton should help you out. i'm not sure if ford ever ran the pump of an oil pressure switch like chevy's. let me know what you find. most library's have factory repair manuals. good luck

Booner36. Having same problem with my 89 and found your post will searching for solution. Did you ever track down your problem. I am suspection the Ignition Switch but havn't pulled it apart yet. Thanks.