I don't know where some of these others come from but when I see a set of 4 coils on a single unit I call that a coilpack.
Pull the coil and look at it carefully on the outer case in bright light. These commonly crack small cracks that can be just about anywhere on the coil case plastic. It is VERY common to misfire only in little bits on these, I've lost 4 now to it and not a one misfired 100% of the time, only very slight cutouts under load, they idled and low load/rpm beautifully. The cracks let moisture in to corrode wires, the miss will be very light at first. I never registered a single DTC during all fails. Look VERY close at the wiring going right into module too, common for wires to crack there at insulation to make same problem, they were too cheap and the wireloom there is too short, MAF sensor pulls loom the other way to crack wires at coil connector. You can buy the connector, I rebuilt one for mine for maybe $2.