not sure on the 6n2 what it does, but either way if it were the immo it would be logging faults, so if you are not seeing coil / immo related faults i would indeed look elsewhere.

not sure on the 6n2 (only had one through the officer wreckers ) but do they have a hall sensor on them? that can fail which would exhibit what you are seeing (been there done that).. can you see if there is spark coming from the actual coil itself?