I've been having a random misfire code pop up (P0300, like twice a month) for a long time. It never landed on a cylinder and it only happened during 5th gear cruising below 2000 rpms and the rest of the cars driving and performance has been great. I have replaced or checked almost everything during normal maintenance and as I had time and patience. I figured it was just a gremlin in the system.
I developed a bog at WOT just before the holidays after my fuel pump swap (upgrade) and fuel injector cleaning (maintenance) and new plugs. I was kind of spooked, but I checked fuel pressure at WOT and that was definitely not it. My fuel system is solid. It better be, everything is almost brand new or recently checked. I had a spare set of coil/wires and swapped it in...No bog and after driving the car for several weeks, no more P0300. I never thought the coil would be the cause since it was a new MOPAR coil pack from Dec 2020 with less than 15k miles on it. Also when coil packs go, they usually go in a pretty obvious fashion. I guess this one was never good in the first place.