I started smelling fuel around my 04FX4 today. Seams to be coming from the top middle of the fuel tank when the truck is running. Does anyone have any ideas?

 

Yep. At the top of the gas tank, there's a metal round cover/ seal that's held down by several bolts, or a ring that can be "tapped" counter clockwise to remove this cover....this cover also has a fuel line that runs up to the engine which feeds the fuel rails; the fuel rails feed the fuel injectors; this cover also has a wiring harness that connects to the fuel pump (in the gas tank). This cover would be removed to gain access to the electric fuel pump (submersible) inside the tank; the cover has a gasket (some use an O-ring) to seal the cover to the gas tank. I suspect this gasket/O-ring is bad, or the connection of the fuel line from the cover to fuel rails running to the engine perhaps has a crack. If this were the case though, you'd have a good stream of fuel being pumped out this crack when the fuel pump is running, and you'd see this steam of fuel.

That or the filler neck tube (gas cap filler tube to tank) is suspect.

 

Thanks, what I find was a crack right on the pump assembly top, right at the outlet. Fuel would spray when pump was operating. Had to change the fuel pump assembly. I was able to re-use the fuel lines. George