I smell gas in the cabin of my 2006 ford f150 gas gauge doesn't move but I see no leak

When you say the fuel gauge is not moving -- you mean it does not work? This would be an indicator of a sending unit or fuel gauge concern, or perhaps a wiring issue. If you are smelling fuel, there is either a fuel leak or a fuel vapor leak. Either way, a "smoke" test should be performed, introducing a vapor into the fuel system to see where the smoke leaks out of -- this way determining where a leak may be occurring.