Q: We live in the suburbs of Chicago and drive a 2015 Dodge Caravan, for which it's recommended to use regular gas rated at 87 octane level. We just completed a road trip to Seattle and the gas stations in the Western states showed the regular gas with an octane rating of 85. Do cars at higher elevations run just fine on the 85 regular octane rating? Could I have saved money by purchasing regular gas instead of midgrade?
M.V., Darien, Illinois
A: At higher altitudes, the air is less dense. To maintain the air/fuel ratio, lower octane is acceptable. Modern cars adjust for changes in altitude and the driver never notices any difference in performance. That’s almost as cool as your phone’s clock changing with time zones.
