It's the car my partner uses every day, and as I have an identical car, maybe I'll swap the sensors over, Then I can take my time to investigate because I don't need to go out and work every day., nor will I let it run out of fuel I suspect there's a dead spot on the track because it does work fine down to about half-full. What I don't know is if the reading would come back again as the tank continues to empty, once the wiper gets past the dead spot. I have come across these on crane joysticks where if you hit a certain point the hoist comes back to a creep speed.