1997 Pathfinder missing at low idle

[Sifujon]

This vehicle was having issues with firing for months now. Replaced the plugs, wires, cap and rotor, and fuel pump so far and it's MOSTLY solved. However now the problem is misfiring at low idle, especially when it's warm and/or humid. It runs fine otherwise, just missing at idle so sometimes when I'm stopped I'll put it in Neutral to raise the RPM and make it stop.

I think last time I checked the codes there was one for the knock sensor. Our guesses at problems were either vacuum leak (I don't believe there is one, but I'm checking again), O2 sensor, or maybe a clogged PCV. Am I missing anything?