No, it's not normal, and unfortunately you can't query the ECU for the fuel level. In our cars, the fuel sender unit in the fuel tank is wired directly to the gauge on the dash - the ECU doesn't know how much fuel is in the tank (or at least, the standard OBD PID code for fuel level isn't being used). It means you probably have a faulty electrical connection.
There are only two places I'd look, really. First is the plug on the top of the fuel tank. These are finicky to get on right - they really need to be pushed on hard. It's something occasionally overlooked by those working on the tank (eg someone fitting a long range tank).
The other is the stereo (and there's a way to test it and a way to fix it. While that might sound odd, the stereo shares an earth with the instrument cluster, and the fuel gauge needs an earth to operate. If that earth is failing in some way, there goes the gauge. So, to test that - get a piece of wire and connect the chassis of the stereo to any exposed metal under the dash. It's safe - it's supposed to be earthed. If that fixes the needle, make the wire permanent.
There are only two places I'd look, really. First is the plug on the top of the fuel tank. These are finicky to get on right - they really need to be pushed on hard. It's something occasionally overlooked by those working on the tank (eg someone fitting a long range tank).
The other is the stereo (and there's a way to test it and a way to fix it. While that might sound odd, the stereo shares an earth with the instrument cluster, and the fuel gauge needs an earth to operate. If that earth is failing in some way, there goes the gauge. So, to test that - get a piece of wire and connect the chassis of the stereo to any exposed metal under the dash. It's safe - it's supposed to be earthed. If that fixes the needle, make the wire permanent.
