Confusing misfire issue
 

So I finally got an spark tester because my idle is quite often a little rough. Its not super rough but its enough to hear it, I can see the needle wiggling and the exhaust quietly changing pitch.
I read the misfire thread and its none of those things.
I have d585 coils, brand new leads and plugs. I already checked the grounds and they are fine.

Leading 1 seems to be fine. But when I put the spark tester on Trailing 1 and Leading 2 its pretty easy to see that its misfiring. Whats also strange is my CEL doesn't flash to tell me there is a misfire either. And this problem does not occur at higher RPM. ONLY at idle.

I wouldn't say this is really an issue, just a minor annoyance to be fixed eventually. Its certainly not a priority.

When you say easy to see.... what are you seeing?

Instead of a steady pulse as there is on Leading 1, the light randomly goes out and comes on which coincides with the drops in RPM.

Try swapping whatever coil is doing that to another position and see if the problem follows.

I know your coils are new, but duds happen.

Okay thats the next thing on my list to do then right after an oil change. I'll let you know what I find.

Did you make any change/upgrade shortly before it happened?

lots of possibilities though..

could be electronics, relay, air sensor, 02 sensor, etc.

could be wear and tear of the coils, plugs, wires.