Originally Posted by Guzz
To be honest, put a piece of black electrical tape over the RID fuel gauge, and just pay attention to your odometer. The fuel gauge is for entertainment purposes only.
Not true, the gauge works reliably if the sender tracks are cleaned carefully with a Q tip soaked in contact cleaner each time the fuel filter is changed (they tend to build up with an oxide that comes from the fuel)
The other thing that needs attention is the connector to the tank. BMW should have used Gold Plated pins & sockets there but instead just use Tin Plated ones. These must be clean and void of any oxide and then coated with dielectric grease to stop any further oxidation.
I have serviced/repaired quite a few doing the above with great results.