98 z-71 gas gauge pointer vibarating

HELP !!!! the gas gauge on my 1998 Z-71, is acting weird.
when starting, it moves over past full real quick
the back to gas level.
It vibarates (shakes)
thanks

I have the same year and z71 model truck.

I had my fuel pump replaced about two months ago.

The fuel needle started doing the exact same thing about one month ago.
I took it back to the dealer thinking it was a wiring problem.
The tech said that even with the fuel pump totally unplugged, it still did the same thing.
He said it had to be something in the instrument cluster.

I haven't fixed it yet and it is still doing it.

FYI

My guage swings wildly when the vehicle is in motion and I believe it is the sending unit. As they are very expensive, I'll just live with it since it is accurate (sorta) at rest. I wonder if they have a compensator component in the sending unit that fails.