Snug the fuel lid down on the gasket, do not overtighten. Turn the key to the 'ON' position without cranking the engine. Check the fuel bowl for leaks; check the drain tube under the truck for leaks.
Turn the key off and then back to 'ON' until the pump stops and you can no longer hear the familiar 'buzz' from under the driver's seat. Do this a total of three times and give both the fuel bowl and drain tube one more check for leaks.