That is the most likely thing... It's the last GM gasser for trucks that has peak torque down low
Hopefully they at least give it a little different tuning for the trucks... It's a peppy little engine, but you've gotta wind it out to really get it going.
I'm sure it'll be tuned differently, it's pretty easy to move power bands around with modern VVT and ignition systems.
DI is overrated. BMWs are having massive problems keeping their intake valves clean because there's nothing to clean them.
Hell, that's the WHOLE reason why injectors are positioned where they are in the intake stream.
It does seem a lot of manufactures have been having trouble with carbon build-up on DI engines. Ford, Audi, BMW but for some reason GM doesn't seem to be having many problems. I've seen many worried about carbon buildup on GM's 3.6 but never actually seen anyone that has experienced it. I believe they redesigned the PCV system to be much cleaner and use the VVT to trap gases in the combustion chambers to do away with EGR.

