Yader

I had the same issue. With my Chevrolet Silverado 1500 2024. i went one day from doing 22 mpg and the next day 10mpg without towing anything and my range of miles to full tank was 466 and the next time I filled up it gave me 276 gallon to full tank. It been like 4 days and it have not change. The dealer says it nothing wrong. I don’t trust them. I am not an aggressive driver and was not driving more then 65 miles. I will go to dealership next time and have them show me another vehicle line my and see how much the full tank will show in miles I will guaranteed it will be around 460. I was doing 9 MPG heading to Miami driving 65 miles.