I'm a newbie here with the same issue as Talaly.
6 months ago I purchased a 2006 X5 for the wife. The car was well maintained by a BMW dealership and was in excellent condition. It's got the 3.0 liter engine and has 90,000 miles on it. It runs and handles like brand new and is a beautiful car.
About two months after I got it, the fuel guage reads empty. I have read that using low quality fuels can cause problems with the sending unit. I ran two full tanks with injection cleaner and switched to Shell gasoline hoping this would solve the problem but no luck.
Is there any way to determine which sending unit is bad before I purchase one? I don't feel like spending extra money buying the right hand sender with pump and the left sender as well.
I have also heard that the guage itself could be faulty. Is there any way to check this as well to verify that the guage is fine and the problem lies with one of the sending units?
Any light you guys could shed on this problem would be greatly appreciated. THANKS!!