P0305 Cylinder Misfire

EZT

Afternoon Gents.

2009 255K Miles
R2C Intakes
Art pipes/FI exhaust
Oil change 5K ago

Filled Z from empty to full Thursday morning on way to office. Traffic of course ground to a halt, and I immediately noticed my exhaust note discernibly changed, accompanied by an SES light. I was only a few miles away from office and plugged my OBDII scanner in and obtained the P0305. Rough idle, lots of vibration, some extra fuel smell, but made it back home.

Checked plugs Friday, #5 was significantly darker than the rest. Figured new plugs would do the trick so I put a new set of NGKs in today. Also cleaned the throttle bodies as they definitely needed it. Additionally, tested coil packs with a multimeter and all appeared fine for resistance.

Reassembled everything. Rough idle over 1K still. Ran through all of motorvates videos for after cleaning throttle bodies, cleared codes, and drove for 10 minutes. At this time, the lovely P0300 popped up. However, after running through the idle relearn and clearing codes only P0305 remains. Idle is back down near 700, but definitely not running right. Feels jittery especially when placing in drive.

Any further thoughts for the culprit? I know this one can be so many things. Was considering swapping the coil pack with another just to see if the misfire moved cylinders.