Fuel gauge problems, 2005 Prostar 205

[RickH]

I have a strange one on my 05 Prostar 205. Fuel gauge stays on full until level gets very low then it moves all at once to just about the empty reading. I have changed the sending unit and also put in a new fuel gauge just to eliminate that question. The strange thing is I can unscrew the sending unit and hold it in a few up and down gas levels and it actually shows a reading on the fuel gauge but when I screw it back in place it goes back to full and stays there etc. Any suggestions would be greatly appreciated........

Rick