I had the same problem with my fuel guage, when I would turn the key on it would only rise about an 1/8th inch. So after reading this thread I decided to try the grounding wire trick and pulled the sending unit out of the tank. Turns out that my problem wasn't the ground it was that the little metal arm inside the sending unit had broken off. Easy fix to just solder it back together. Sorry I didn't take a picture.
