Re: feul gauge works intermittently
carefully check all wiring connections for tightness and corrosion, if all tests ok its either the sender or the gauge.
so far there is not a good way to test either.
does your display disapear? does it revert to zero?
the fuel management meter has a lot of functions, are any other functions working improperly?
the miles per gallon is a calculated function based on inputs from either a speedometer or GPS unit. if all thats affected is the MPG function it could bve a speedo or GPS malfunction as well.