Last Monday I went out to start up the HD and head up to my dads to install my new Magnaflow muffler. The truck fires right up, and immediately the "low fuel" light comes on in the message center and the fuel gauge is buried below "E". I initially think, with this things fuel efficiency its no suprise its empty again. But, then I think, I just filled this up recently. So I go back thru my gas receipts, and sure enough, I had just put gas in it on the Thursday before. 26 gallons to be exact. I think back about my trips I had made and knew I had only gone about 50 miles total, if that. I'm starting to run the scenario through my head, wondering if some low life siphoned out my 26 gallons.
I ended up going up to my dads, and working on my exhaust until late that night. The next morning I dump about a gallon in the truck outta my gas can, and head off to the closest gas station. The pump clicks off at $10, and the truck is completly full. I drove it all last week, and still the gauge is buried on "E".
So I'm just wondering if anyone else has run into this with their trucks. Bad sending unit, faulty sensors, wire off sending unit or a sensor.......???? I have yet to plug in my scanner to check for any codes, but I doubt I'll have any luck with that anyway.
Ideas???

Did you weld on the truck while doing the exhaust work, if so did you unhook the batteries? May have a blown fuse.

Nah, the fuel gauge wasn't working before any of the exhaust work was done. It was working fine, IIRC, on Sunday when I went to Home Depot for supplies for the house. I would have noticed the brightass yellow "Low Fuel" in the message center I would think. But, then Monday when I went to go work on the exhaust, it was on and "empty".

CHECK FOR CODES. Depending on the code, my fuel gauge will do the same thing on the next restart cycle. I know it does it for sure when it sets the
P0302 code. I thought my sending unit was going bad until I reset the code and the gauge immediately went up to the correct level.

Alright I'll have to run the scanner and see what I come up with.

A couple of other people on other forums said they've had the same issue, and it turned out to be a bad sending unit. But, unfortunately the sending unit and fuel pump are one unit.