[nalinc23]

Hello all, my dad finally traded in his 04 Duramax work truck standard cab for something a little more suited for daily driving, a Sierra Denali. It is white, beautiful, and to be honest I'm pretty jealous. Anyway, just a question for those familiar with the truck:

Does the Denali require premium fuel? Also is the engine the L99 or a different variant of the 6.2 L?

He seems to think regular is fine because it doesn't say anywhere on the gas cap or manual that it requires 92-93 octane. Let me know!