Unless you get a mid grade or premium tune, anything over 87 is a waste. a 93 tune really wakes up the truck.

 

 

Don't throw stones at me, but from the manual

" Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87 or regular unleaded gasoline blended with a maximum of 85% ethanol (E85).
Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. We do not recommend these fuels.

For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing (page 279).

Do not use any fuel other than those recommended because they could lead to engine damage that will not be covered by the vehicle Warranty.
Note: Use of any fuel other than those recommended can impair the emission control system and cause a loss of vehicle performance."

I use 87, since my tests with 91 did achieve a slight better mileage per tank, but offsetting the cost per liter it was more expensive to use.
Also was not worth the apparently better "boost", because I drive mainly on clogged city traffic, so it would be a waste.

 

 

^^^ Moral of my story? Exactly what eMike said!! ^^^

 

I mainly run E85 mine every once in a while ill run some 93 in it.

 

87 only..
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I always run it on 87. I should run 91 for a while just to see if I notice anything.
Not sure if 89 is actually worth the 10 cents more...