96 Bronco Fuel Tank Sending unit.

November of 2008 Ford Service replaced the fuel Tank Sending unit. Since then the unit has been replaced seven (7) times. It lasts a week or so and then the new unit develops a dead spot which causes the gauge, actually it's a meter, to float. The needle just wanders all over the face, sometimes floating way past the full mark, regardless of tank level. Eventuall the fuel will burn down past that dead spot and the gauge/meter will read normally until the float hits another dead spot. Ford is at a loss. They just keep replacing sending units. I have had to change dealers a couple of times from their Service Managers telling me they were at a loss as how to fix the vehicle and not bring the vehile back to them, as all Ford service dealers are independant business units and don't have to accept a particular vehicle in their shop. Any help would be appreciated.

I would check the wiring harness for a worn spot running from the sending unit to the gage. Also check the electrical connections.