So I went back to the dealer today to see about getting back into my trade- in (2008 Duramax) and they said it has already been sent off to auction. I tried explaining to them that I basically hate this truck and it was a horrible decision trading my old duramax for it. I have about 3-4 tanks through it with about 1100 on the truck total. I drive 60 miles round trip daily with 90% of it being highway with cruise set at 70, my best tank has been 22.8. I have tried telling the dealer that there has to be an issue with my truck since I am getting that mileage but of course no cel= no problem. Yes it is a lot easier to drive than my old truck, it's more like a smaller suv. But going from my old duramax to this canyon, I am dreading my decision for the sole purpose of the trade off was to get the better mileage, but I had a whole lot bigger, better truck. Oh well I guess lesson learned.