Test your mileage vs. fuel quality. You have a trip odometer so it's easy to test different grades of gas 10 gallons at a time, to make the math easier. My wife's '16 Honda Pilot and my '09 Chevy 3500 get 30% more miles from a gallon of 91 octane non-ethanol than with 87 octane ethanol. The premium gas gets 20% more miles/gal than 89 octane ethanol. Fuels are usually priced according to energy content. For the health of your fuel injectors, don't forget the detergent package; high detergent brands include Shell, Holiday, Philips, Exxon, and now Cenex.