2018 Dodge Ram 0306 code

Hi, I have a Dodge Ram Laramie Hemi 167k on the clock. I changed the spark plugs. And began getting a 0306 (cyl.6 misfire). I swapped the coil to another cylinder 0306 remained. I tested and swapped the Fuel Injector 0306 remained. I tested the injector wiring with a test light I can see the pulses to the injector. I inspected the cabling to both the coil and the injector, no readily apparen issues. Any ideas?