My gas mileage in my 2017 Hybrid has gone from 37 mpg to 24 mpg all of a sudden. I took it into the dealer and they blame bad gas but I'm not believing that one. I have bought gas from 3 different stations since this issue has happened and nothing changes. I also have read that the cold winter temps could be the issue or running the heater. But, I didn't have this issue the past 2 winter's that I have had the car. Tire pressure is good... does anyone have any other suggestions of what it could be?