I have an 04 pacifica last eight on vin 5R371677. when i fill the tank, after driving for a while my gauge went down to empty, when i checked the tank i found the right side of the tank full and the left side of tank empty, i didn't know how to check the fuel sending units to see how they worked so i changed the primary sending unit on the left side and the module on the right side of the tank. still does the same thing when i put gas in it all the fuel gets sucked to the right (pass) side of the tank and the drivers side gets sucked dry and the car runs out of gas even though the right side of the tank is full............please help.....