Ditto on the vacuum or air leak. Rule that out before you start changing electronics.
One of the coils went out and I had P0306, Cylinder 6 Misfire Detected, come up on my friends code reader. Also 3 of the coils were ripped in half. So that is why I replaced them all.
I didn't mean to call into question your first repair, I was speaking from personal experience. I had a strange misfire and I couldn't imagine that it was anything BUT a bad sensor or electronic piece. Turned out to be a leak.
Demonstrated vividly by spraying some intake cleaner around the leak and listening to the engine stumble