hey, it sounds like you have a dodgy ignition amplifier within the coil pack.
my suggestion is to run the car without the coil pack cover temporary and then with the engine running unplug one by one. to diagnose which cyc is misfiring.
if you unplug it and the engine changes then that coil pack/cyc is still good. keep doing that to all 6 cyc until you notice the one when you unplug does not changes >>means that cyc isn't firing (hope that makes sense)
once you do that... you know its that cyc thats misfiring. so its either most likely the injector or coil pack (90% of the time its coil packs).
to narrow it down 100% its the coil pack that is playing up you swap the coil pack from the cylinder that isnt firing with another cylinder that is firing.
and last of all once swapped, you unplug the coil packs you have just swapped over and see if the problem has moved onto the cylinder you have just swapped, if it has moved onto the cyc you swapped then you know its def the coil pack that is dead/playing up
and because it does it only when its warm... you may be able to get away by insulating it with tape or other stuff sau members have recommended. if that doesn't work buy a replacement coil pack
hope that helps!!! just from my experience of misfire its a headache!
goodluck
chris