Update...
As I removed the multimeter from my travel tool bag, the wire ripped out of one of the leads and broke. Since I already have a higher quality one at home, I can't convince myself that I absolutely NEED to go buy another backup multimeter...
Through empirical evidence, however, I think I have confirmed the grounding wire is the main problem causing the vertical cylinder to not fire ~50% of the time. It's also binary... It either works perfectly, or not at all, which to me sounds like an electrical problem. I've found that by keeping the ground wire oriented up out of the coil mount, it works almost 100% of the time, but if I mount it like the other cylinder's wire, it works 50% of the time. The picture below shows the misbehaving wire circled and mounted upright, and an arrow pointing to the dent on the top of the same coil.
My biggest problem is how to fix the wire that seems to be shorted somewhere inside. It disappears into a bundle of other wires, and I am NOT an electrician by any stretch of the imagination. Of course, I still am without a garage or normal tools until the end of the month, as I'm still traveling for work.
