[shifty]

Pretty sure the fuel level gauge is controlled by the float attached to the pump. Based on float position, voltage will vary, indicating the correct position of the gauge needle.

While researching fuel pump/tank pressure/emissions issues in my truck, I saw a couple of different videos on YouTube where people said jumpy fuel gauge is bad sender on the pump assembly, or more common, the ground near the tank/filler is loose/failed/detached and the lack of solid ground is causing electrical issues.

Dunno where that ground would be on your crew cab, but on my 98 extended cab, it goes from the top of the tank to the framerail roughly between the filler neck and the forward-most driver bed mount bolt.

Being it's pretty cheap (free and quick) to check a ground strap, may be worthwhile. Beats pulling the pump and/or the cluster to check for grounding on those two.

I don't know if the gauge gets the voltage direct or by way of PCM. If it's via PCM, maybe a diag tool would let you probe the voltage to see if it's getting fluctuation, thus it's not the cluster that's the problem...