Hi and thanks for using 2CarPros.
Honestly, that is most likely because of the small amount of change in the tank. The float and rheostat may not be sensitive enough to pick up on that amount.
In a perfect world, it should. The only thing I could suggest is to remove the fuel pump and replace the float and rheostat in the tank. Since the vehicle is still under warranty, I would take it to a dealer and discuss it.
Let me know if you have other questions.
Take care,
Joe
Sunday, December 23rd, 2018 AT 6:23 PM