fuel gauge problem

[mainermikeyd]

ok guys you helped me perfectly with my last question, got another one for ya. My new toy is a 85 K20 4x4 with a 82 Sierra cab, (Northern Maine winters), my problem is the chasis had dual tanks, cab had single, fuel gauge is pegged past full, I have checked, an installed a new ground from fuel tank. Going to install a new tank eventually (drivers side is one missing), where do I start my diagnosis from here?? Any help, or suggestions will be greatly appreciated thanks