1998 Explorer fuel (gas) gauge issue

[jloxterkamp]

I have a 1998 Explorer that the fuel gauge only reads correctly after the ignition switch has been shut off. Basically, the tank gets filled up, but gauge will not move from full until you stop, shut the engine off, and then at least turn the switch to the 'run' position. Then it does read correct at that moment, but not again until you stop.
Any ideas on what to check? Thanks!