After I upgraded the fuelpump in 2017 my fuel level gauge started acting up.
I ran out of fuel when the gauge showed 1/4. This happend several times causing a lot of grief.
Based on reports on m.net this is pretty common after changing the pump.

During the winter a managed to get enough motivation to have a look at the problem.
The sending unit is exposed to the fuel as it's being part of the assembly that submerged in the tank along with the pump.

All I did was to inspect and clean the contact surface for the brushes that moves when the fuel level changes.

I also made sure the level arm was all free without any chance of touching other parts trough the operating range. I looked ok but i slightly bendt it outwards to be sure.

So far after a couple of tanks of gas it seemed to have fixed the problem. My guess it was the arm and not the level sensor itself.