I have a 2004 2500HD 4x4 with a duramax of course. My fuel gauge has stopped reading. It started going bad about 8 mos ago. It wouldread fine from full down to a half. And then when it would get to the half mark it would bounce between empty and a half. Now it has stopped reading all together. I bought a used sending unit and put it in and still no change. The only thing different now is, everynow and then when I start the truck the fuel guage will read full for 10-20 seconds then it will go back to empty. As there any chance it's a bad cluster or do I need to go and buy a brand new sending unit from GM.

Thanks for any help yall can provide.

Does anyone have any ideas for me?