When I try to fill my tank up, the fuel builds up in the filler neck if I let any more than a trickle out of the nozzle. It is most likely a pressure release problem. It started immediately after I had the fuel pump replaced last year. Mechanic said the old filler neck was junk, so he put a used one in. I ordered a new one recently, thinking that was the problem, but it has a relief valve hose that doesn't seem to have a place to connect to on the fuel tank. I believe these fuel tanks are pressurized (?) So that may have something to do with it.

So I'm not sure where to go from here, I'm stumped. I pulled the bed off to get a look at the whole system, but I can't figure it out.

 

vehicle? do you drive on dirt roads or dusty areas much?

 

This is the silverado forum, right? Anyway, it's a 2000 Silverado 1500

 

the recirculation tube in the filler neck draws air out of the tank during refueling...find the connection to the tank, make sure air can pass, hook it up. its purpose is more vapour recovery during fueling but it also vents the tank.
the tank also must vent to the evap canister to fill properly. the vent line from the tank to the canister, out the vent solenoid and to the vent filter must all be clear or the tank will fill slow.