The use of premium gasoline in a BMW X5 will not significantly improve mileage. BMW recommends premium gasoline for optimal performance, but the difference in fuel efficiency between premium and regular gasoline is typically negligible. According to the U.S. Department of Energy, the difference in fuel economy between premium and regular gasoline is only about 1-2%.
For best fuel efficiency, it is more important to follow proper maintenance procedures, such as regular oil changes and tire rotations, and to drive in a fuel-efficient manner, such as avoiding rapid acceleration and deceleration.
