I've had my new 2012 RAM 1500 express hemi since 12/31 (about five weeks), and let me say, I'm thoroughly impressed with the gas mileage compared to my previous vehicle, a 2006 Dakota 4.7l v8. I'm still driving around on a quarter tank from when I filled up about three weeks ago. I don't have any hard numbers for comparison, but that wouldn't be the case in my old truck. It must be the cylinder deactivation.