I had the same truck back in the 90's. Bought new in 92, sold it in 01. There was a safety recall on those trucks for that problem. It's a bad design/problem with the selector valve that let's you switch from one tank to the other.
The tank is really not sucking from the other. Since the engine is efi it doesn't use all the fuel that is pumped to the engine. The fuel pressure regulator bypasses it back to the tank. It's SUPPOSED to bypass it back to the tank you are using at the time. It's switch is stuck and it's sending all the bypassed fuel to the front tank.
I would have a dealer run the VIN # and see if the recall was ever done. If not, it should be a free repair.
Recall # info:
1992 Ford F-150 Recalls
Recall ID# 93V125000 - FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY
Recall ID# 01I008000 - FUEL SYSTEM, GASOLINE
More:
http://www.automotive.com/1992/49/ford/f-150/recalls/54164.html
The tank is really not sucking from the other. Since the engine is efi it doesn't use all the fuel that is pumped to the engine. The fuel pressure regulator bypasses it back to the tank. It's SUPPOSED to bypass it back to the tank you are using at the time. It's switch is stuck and it's sending all the bypassed fuel to the front tank.
I would have a dealer run the VIN # and see if the recall was ever done. If not, it should be a free repair.
Recall # info:
1992 Ford F-150 Recalls
Recall ID# 93V125000 - FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY
Recall ID# 01I008000 - FUEL SYSTEM, GASOLINE
More:
http://www.automotive.com/1992/49/ford/f-150/recalls/54164.html
