Hello Everyone! I just picked up my 2021 Sierra 1500 AT4 with the LM2 Line 6. I have put 900 miles on it and the best fuel economy I have achieved is still below 25 mpg on the highway. Full disclosure, I'm in Alaska and the temps have been hovering around zero consistently, but even with using Diesel #1 up here, I still figured I'd be able to achieve higher numbers than that. I had an 09 6.6l sierra that I could get 24mpg out of on the Highway, and my 328d BMW gets a whopping 44+ mpg on the highway in the summer, and as high as 40mpg on the highway in winter driving. What is everyone else getting on their LM2 engines? And yes, I'm driving it SUPER EASY and still not getting anything near the EPA ratings.