I get 20-21 mpg everyday driving….17-18 pulling my boat….and thats running 65-70 down the interstate. Yes, 6.2 420hp. It is definitely a pulling and driving machine.
Yes, it does have flex fuel system. I also only run 91-93 100% gas. The higher octane might help….not sure. I bought a GMC because of the new front end. You could same a little $ buying basically the same set up in Chevy.