Does anyone know of any websites that sell a fuel sending unit for a 1973 Cadillac Coupe DeVille?Also,hetre's the problem..My gas gauge is acting funny.I put gas in my car,but my fuel gauge didn't register at first.Then after a few days,it went up to a quarter of a tank,then stuck there for a while.A few days later I put more gas(for sake of mind) and it bumped up to a little over half a tank,then I drove around and when I stopped at a stopsign,it bumped up to a little over 3/4 of a tank,but won't go back down..Anyone know what might cause this??