Fuel sensor?

[PABLO]

hi guys, my grand mother has a e36 328i 97. The problem is that sometimes the fuel gauge indicates that the tank is empty when i have just filled in. I think its a bad fuel level sensor. What do you guys think and how can i solve it.
Thanks

[shogun]

Maybe this one helps a bit. Here is a nice description how to clean the fuel sender on an E32
http://shrubbery.student.utwente.nl/johan/fuel_sender/fuel_sender.html