I have a 2002 Nissan Pathfinder that requires 91 octane gas. Until recently, I have only been able to get 89 or 93 octane, so I have been using 93. Now i can get 91 octane at the local 7/11. The funny thing is my car is getting better gas mileage now than with the 93 octane. I tried 87 and 89 but got terrible gas mileage. My question is if I am somewhere where 91 is not available, can I use equal parts of 93 and 89 octane and get the same results??
Yes
That’s what the stations do. They only have one low grade and one high grade holding tank and the pump does the mixing for mid grades.