87 (86) Octane and high altitude 7.3L

[Evolrider]

I have the 7.3L and live at altitude 5800 ft. most if not all of our regular unleaded gas is 86 octane here. The manual clearly states even at altitude to run 87 or higher. I only run top tier fuel (mainly Costco) in my trucks, last truck was a 2014 F150 3.5L EB and never had an issue with the 86 octane. Being that Costco only sells regular or super unleaded what are your thoughts on running 86 compared to splurging on super unleaded to meet the minimum requirements?

 

[strogg]

I'd make sure you don't drop down to lower altitudes while you have lower octane still in the tank. That'd be my main concern.

 

[Evolrider]

I agree that putting higher octane in before traveling to lower altitude makes sense but does 1 octane rating really make that big of a difference for daily driving? I would be more concerned putting 87 octane in at 7-eleven than 86 at costco

 

[soulezoo]

You should be just fine as long as you are just daily driving, not hammering the throttle or towing a whole lot. The computer will adjust to a certain extent. If you're in hot weather, towing heavy and using a lot of throttle, then you need to octane up.