I replaced the fuel gauge in my '78 cj. And now I have two problems. One, it will not register FULL when the tank is full. Is there a way to callibrate the sending unit? Second, (espicially when it's damp outside) the gauge moves from half tank to beyond empty constantly. Is that due to a bad ground? Is so, what would be a better ground for the sending unit?

Thanks. That is all for now.