Well....that's an ouch.
The Four-Cylinder Chevrolet Silverado Got Worse Fuel Economy Than the V-8 in Our Test
Sounds to me like the tests weren't run on the same day (temps/winds can make big difference so I wonder how much they considered this, or if they just decided it would make a good article...to heck with the details!) but maybe I missed something. That said, it still doesn't look good at all when your fuel efficient option is not really all that fuel efficient. I'm betting if the trucks were ran at 65 or 70 mph instead of 75, the tables may have been turned. (75mph around my area is pretty much the fastest anyone drives, so that seems a little fast to me, but I know its not in many other places)
Starting to wonder if this engine will be regarded as a fail? There is speculation the 2.7 might be perfect in the midsize trucks (which I kind of agree with...except for...) but if they can't squeeze any better mileage, or if it ends up being worse than the 3.6 (with its 4 cylinder mode) then I don't think GM will put the engine in those trucks either. So then you have a small but torquey engine that nobody wants in their FS trucks.