I have a 02 Monte ss, the first problem is my fuel hand floats and reads incorrect, I read on another forum you can just go off the digital reader by the sun roof but I've knoticed it also changes as my fuel hand floats. The second problem is my digital odometer doesn't work and I'd like to get an idea of how to fix it before I dog into unknown territories, the digital numbers aren't showing, maybe its just the lights I'm not sure.

 

Sounds like it's not your stepper motor causing the weird fuel gauge readings if the same behavior is seen with the digital read out. Perhaps the fuel sending unit has been swapped with one that is more touchy? My 84 Camaro fuel gauge was crazy responsive to fuel sloshing in the tank.

As for the digital odometer, this is semi-common on Montes and Impalas. I've come across reading posts on other google searches about components on the board that need replaced and then it's as good as knew. Unfortunately I never book marked those links

 

I would assume it's the float on the fuel pump giving inaccurate readings. Since the overhead also is affected