[QUOTE=Mr. Dan;707613]I don't like to argue but I do like to take pictures. I have a '14 GMC Sierra SLT with the 6.2L engine and the Max Trailering Package (what the ordering system called it). Regarding octane usage, I found this on page 9-69 of my Owner Manual:
I don't know if the design engineers know this paragraph got slipped into the manual, but it does not say premium fuel is "required".
The following is a picture of the label inside my fuel fill door.
I've been told Recommended does not have the same meaning as Required
I usually run 89 octane mid-grade gasoline. I've never heard 1 knock and it's a beast towing and getting groceries and passing slow vehicles!
Here in Canada Regular 87 Octane is $1.30 a litre. Mid grade $1.35, Premium $1.42 and Diesel is low right now $1.21. These prices are per litre. Premium is a killer and of that was required I certainly would look at Diesel when buying new truck.