Wildly fluctuating fuel gauge

Started out wildly fluctuating back and forth, with some pauses that started again after hitting a bump, but only for the first 50 miles on a new full tank of gas. This happened whether I was sitting still or moving. After that it seemed to be accurate. Now it is always moving around, not just when I hit a bump, moving or still, and not only on the first 50 miles. Also, it never seems to be accurate anymore. Fuel float? This happened after owning the truck for 2 years with no problems. Seemed to start after an electrical surge last summer that fried a couple of fuses, but everything else seems fine.

Check tank grounds and sending unit plug in.

The fuel gauge works off of ohm restiance.
Hook up a volt meter and while driving see if ohms flunciate or if it loses ohms.

What year is it?
Also try some injector cleaner in the tank.
Some sending units get barnished up.
MT