Hey there, I have a 99 5.3 silverado. Mine had a similar issue where the gas gauge would come on and tell me a sort of accurate reading and then tell me I was on empty. Or that I was on empty right after a fill up. I bought an fuel sending unit on 1aauto.com that fits it (make sure it has the correct 2 connector peices) to replace it. You could in theory replace just the sender but it’s a million times eaiser to replace the entire thing. I lifted the bed up about 3 feet and replaced the entire thing in about 2 hours. After that I ran it for a little and everything worked fine and has worked fine for about 3-4 months. I made sure it had a lifetime warranty just in the event it might give out again, that way I don’t have to buy another. Hope this helps any