Smile factor w/ the 6.2 is high
, just letting you know! If you are sane about it on the highway, you can get 21MPG. In town, if it is a ton of stop and go...not as good. 5200 miles into mine, about 1500 of it with my 4500lb boat in tow, probably 3000 of it highway, my lifetime is 15.6 average (never reset the second trip odometer). Have one 480 mile trip at 21.2 MPG average (validated by dividing milage by gallons added). Running Costco 92 Octane most of the time, except when I've been not near a Costco, then it was BP ultimate, 93.
I am coming out of a 2013 Vintage 5.3 LTZ Suburban (6spd). The 10 Spd paired w/ the 6.2 shifts like butter, drags my boat like it doesn't exist, and pretty much passes about everything...except the gas station...you will enjoy that HC.