ryanralston07

Me either...usually higher octane goes with more power...never heard of it for gas mileage?

ford_honda

it burns longer so mabey... idk, never heard of it either

BJV269SS

It sort of is what it is...

KillerG

I have had my 2008 King Ranch 4x4 F150 for about two months now, and was averaging around 13.5 mpg city/18 hwy until I did the following:
1. Edge Evo Tuner (set on level 2 with no custom programs)
2. Banks Monster Exhaust (single)
3. Gotts mod

I now average right at 16 mpg in city driving, and about 21 on hwy. I drive alot, so the current mpg's are based on about 4k worth of miles. Bought the Evo for $150 on Craigslist, bought the Banks for $150 on Craigslist, and paid about $10 for the Gotts mod. I'm pleased with the results....
Best thing you can do to improve MPG is the tuner/programmer, then do the Gotts mod and save the CAI money.

Shiny

It is simple really. Better octane gives more power at any given RPM. Meaning you need les fuel to make the same power? In other words less throttle for the same acceleration. But the question is? Is the MPG gain responds to les Dollar Pear Mile? I say Try it first See how far dos 91 octane takes you and how far lesser or greater grad fuel takes you.