RE: 1984 F250 Electric Fuel Pump problems
First I believe that year model cam with a mechanical pump? Is this an after market installed pump? Then does the pump actually shut down electrically or does the motor just die? If it quits running electrical then check for 12v at the pump if it has power the pump is bad if no power then the relay or control voltage is bad (check voltage at relay, trace the wires back from the pump to find the relay). If the motor is dieing and if it’s happening on both tanks then it should be a problem from the transfer vale to the fuel pump. Check the fuel filter and rubber hoses for blockages. If the hose and filter are clear then check the hoses for age and wear (even if they look good the could be soft and sucking closed replace them its does not cost that much).