if you have checked the sending unit then usually it is a wiring problem in your dash.... i am using a non oem one right now..btw the truck loos nice i like the color

ive got a 86 c-10 i figured since we have basically the same truck you might be able to give some advice if you dont mind the gas gauge in my truck doesnt work at all .iknow its not rare for these trucks i just dont know what to do to fix it