xavier

I'm new here and I been reading all topics regarding the issues that I have with my truck, they been very helpful. I need help on a fuel gauge problem , the situation is this , when truck is on the key off position or no key at all, the fuel gauge shows full tank, but when I turn the key on , fuel gauge start dropping and goes to empty, I did the grounding at the tank on yellow wire nothing change , I installed new ground at the tank but no change yet , please help someone.