What could cause a cylinder 2 misfire on my Civic and how do I fix it?

[LoganRJ]

My 2016 Civic’s dashboard just lit up with the check engine light and the car started idling really rough at the stoplight this morning. I plugged in my basic scanner and it’s giving me a P0302 code for a cylinder 2 misfire, but I’m not sure where to go from here since it could be a spark plug, a coil, or maybe even a fuel injector.

[Madison_T]

I had a P0302 on a Civic once. I swapped the coil from cylinder 2 into cylinder 3 and watched the misfire move with the code. That told me the coil pack was the culprit, not the plug.

[MichaelL]

If you haven’t already, check cylinder 2’s spark plug for fouling or oil, then swap the coil from 2 to another cylinder and see if the misfire follows the coil. If it does, you’ll know where to start fixing.

[ZacharyKW]

Another time I chased vacuum leaks and injector fuss for days. It turned out a cracked vacuum line near the intake caused a lean condition that triggered random misfires too. Not always the coil or plug.

[Riley.L]

Quick question: do you have live data showing misfire counts or cylinder trim values? It helps separate ignition from fuel issues without throwing more parts at it.