Ok so i have a 2010 Dodge Journey that i just bought second hand. 160,000 highway miles and it immediately after purchasing threw a check engine light. Maybe it was new, maybe the seller lied to me and covered it up, don't know, don't care. Still have to fix it. Anyway, the code is P-0304 misfire on cylinder #4. You can definitely hear the misfire at idle and feel it when taking off from a red light or stop sign but its not a dead miss. It's not missing 100% of the time. Maybe half the time? First thing i did is swap the injector, plug and coil with cylinder #3 hoping the misfire would end up on the third cylinder, but alas it stayed on number #4. Had a buddy throw a fancy computer on it a get the freeze frame. Confirmed cylinders one, two and three had zero misfires in the previous driving cycle but cylinder four had over 2,000 misfires in the previous drive cycle! Checked all sensors using the same computer and they seem good. Gave a quick inspection to the wires and plugs under the hood and there is nothing obviously wrong. Someone gave me the idea to reflash the computer so i took it in and had that done, to no avail. Put a vacuum gauge in the intake and it fluctuates between 20-21 inches in sync with the misses. Tonight it threw another code P-2311. Ignition coil on cylinder #4 secondary circuit has low ionization. I thought to check the codes AFTER my dumbass messed with a bunch of stuff under the hood, so, i have no clue if it was there earlier today, or if it only popped up as a result of something i did while attempting to diagnose the issue. Anyone have a clue what the hell could be wrong?! I'm at a total loss here!

ran one already. Came back good.

Noone have any suggestions?

I gave the dealer the VIN and they ran it for any recalls. Nothing for the heads or anything.