So I have had a loaner 19 base LT crew cab with the 5.3 L and 17 inch Bridgestone dueller light off road tires for about 3 days now. After a couple trips to work and a back country road trip last night I'm at about 19.2 mpg on the DIC. And that is driving about as conservative as I possibly could. So small sample size but same driver, same trips to work in the 2.7 was a solid 3 mpg better, for me anyway. Your results may vary. Most of my driving was in the 45 to 60 mph range. I bet if it was 72 on the highway the 2.7 would come back to the pack a little more. Also the 2.7 was a double cab with highway tires so that alone is gives it a slight advantage over the 5.3 I am comparing it to. Hope some more members with the 2.7 can share their results. Sent from my Pixel 2 using Tapatalk