my fuel gage gets stuck on half a tank after refueling. i disconnect the batteries and then reconnect and it will go to full. some times it will go to empty then back up to full. the cost of a new sending unit goes between $600 and ford wants $800 , that is just not right. Does anyone know where i can just get a fuel rheostat ? i been checking on line to see if someone figured out how to get one to work in thes tucks?