I've only owned a couple of Chevy's and fuel mileage wasn't on the list of assets with mine. I get the same mileage towing with the 5.4L I got with my previous Hemi powered 2500HD. I don't know what you're towing but, over on the Open Roads forums, folks report about the same mileage with their 6.0L GM's. No one is reporting mileage comparable to diesel towing mileage with their gas engines. I averaged 10.5mpg towing with all four of my Cummins powered Rams. I stop about every 200 miles with my F250 towing but that's mostly due to it's small gas tank with the short bed. I'm already wishing I would have gone with another long bed. I made the same 200~ mile stops with all of them anyhow to stretch a leg, eat, leave a squirt and refuel. My favorite stops are already mapped out regardless of mileage. But a gutless turd? Mine is far from it.