So it’s been like 6 months and I’ve been dealing with this problem. My fuel economy keeps resetting every time I start the car for no reason. I have the setting of it to reset after refuelling but it still resets whenever I start the car.
I know the suggestions; push "reset" or disconnect the battery for half an hour. You can also try deliberately selecting reset on startup, then switch back. Mine only does this (about half the time) when I get well below 100 miles Range.