2014 Summit 5.7 4wd 20" tires swapped to 18", added all skid plates
put 4 cans of techron in it then do a lot of short trips. If it's injectors that may clean them up. I'm surprised the dealer didn't try and sell you on a $200 injector cleaner, that's another option which might be worth a try since most other things have been ruled out. Also cleaning the throttle body might be worth a try.