Non-Operating Fuel gauge!

[E30zone325I]

I'm having a major issue with my fuel guage not working.
The odometer is still working..but the guel gauge has failed.

I noticed when I smack the dashboard it starts to work and be accurate..but later it fails again.
I hate not knowing how much fuel is in my car!

What can I do to repair this issue??

[Chris-W]

Try tightening the small nut behind the gauge on the back of the cluster.

[Alex]

sounds like the screw in the back