I had problems with the fuel gauge on my GDI and found that it gets in a twist if you disconnect the battery when the LCD display is set to something other than the odometer. I don’t know if it’s every reading or just the ones to do with MPG.
So to reset the gauge you need to:-
1, turn the ignition on and set the LCD display to the odometer.
2, turn the ignition off.
3, disconnect the battery for a few minutes.
4, reconnect the battery and all should be good.
This worked for me so I hope it will for you.
Cheers
John.
