Gas gauge only goes to 3/4 and after 100miles an empty alarm comes on ??? on 2001 Mercedes-Benz C320

I find only 5 gallons fills the tank again....Any thoughts...??

Asked by for the 2001 Mercedes-Benz C320
Fuel level sender (Gas level float) has failed and needs replaced.
1 more answer
sender from tank not working. could be sticking or cracked. but not working. have to change it.