fuel meter

Dear friends
I own a 1995 C280 elegance ,I have noticed that the fuel meter is not accurate ,sometimes it gives me a reading which is correct and on the other day it shows well below level,without doing any extra kilometers.
Is that a common problem on this model.What is the action I must take.
Regards
Pierrot Haddad
Beirut-Lebanon.

[euro 287]

Elegance? On the c-class we have had alot of problems with broken wires behind rear seat going to sending unit. Sending unit problems and also instrument cluster problems. Diagnosis is needed in this matter. Find a good technician and have him go in and test the fuel tank sending units .