Gas not registering

Hello, The fuel tank replacement may be your best clue, depending on which came first, the replacement of the fuel tank, or the fuel gauge issue. If the fuel level sending unit was damaged during installation, or the electrical connectors or wiring were stressed, corroded, dirty, or not connected, you will have this issue. Also, the arm inside the tank must be pointing in a direction that allows the arm to move in its complete path. This is impossible to get wrong on factory pump/sending units, but many aftermarket parts allow insertion in any direction. If you have other questions, or need more information, let me know, otherwise, here is a list of certified shops in your area with the training to repair your vehicle: http://repairpal.com/mercedes-benz-within-10-miles-of-richmond-virginia-23231