I think you can play a higher game with your strobe?
The fact that you're not getting a signal from the vertical pot is probably indicative of a poor current in the lead, which would follow if that cylinder is wetting it's plug.
So you could use the strobe as a diagnostic when you swap the coils and the same swapping the leads.
It might not be a strobe problem at all? Once you have a nice fat spark and good current running through the leads I expect the strobe will work okay?
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