so about a week ago I replaced my fuel sending unit, because the fuel gauge was not working at all. it wouldn't move off empty.. got the replacement from late model resto, put it in the tank and now it works... however the gauge reads full for the first 120 miles and doesn't go down, then it will start to move towards empty and be at 1/2 a tank when I am really at a 1/4 tank.. could it be a bad connection to the sending unit or possibly behind the dash?