You're using Regular fuel, right? Not E85? Try a tank of premium. If your truck is using THAT much fuel you'd have to see it in the plugs. For sure the tailpipe.
I would go back and look at your spark plugs for plug-end condition. The color and condition of the plugs tells a meaningful story. If you have a poorly-firing cylinder you should see it on the plugs. Lay them out on a table in order how they go in the truck.
After you take one plug out per cylinder, do a compression test. Watch a couple videos, they explain how. Autozone & OReilly's rents them out at no charge. A leak-down test would be good too. Then remove the rest of the plugs. Again compare notes.
While you're at it, ohm-out each coil, and inspect the plug-end-side for any cracks or electrical burning/traces, etc.
What is the exact fuel pressure? Test that and get a reading. There's a fuel pressure regulator back below the brake booster which often flakes out. Watch a video on that.
Couple other things to note are:
1) What's the MAF voltage? A poor mass air flow senor, even while it CAN technically still be 'good' ...I've seen them come in at the extreme low end of the voltage and a vehicle run like crap (rich), but not throw a MAF code. To test, unplug it, start/run/drive, and the vehicle should run in closed loop but run smoother. They can be cleaned with MAF cleaner (ususally slight improvement), but being a 2012, I'd replace with a new MOPAR (not import) one. Unless it's a Bosch.
2) Temp sensor? They can drift and the vehicle might "Think" it's a different temp than it is. Ohm it out engine-cold, and engine warm. Compare the readings to a Ram ohm/temp table.
3) Air restrictions? Make sure there isn't a mouse nest in your truck's air cleaner box, or something restricting air flow. I've seen it..
4) Vacuum? If you rent a compression tester, rent a vacuum gauge. You could have a vacuum leak. Watch some vacuum gauge videos. Vacuum tells you another story of an engine. ..