I checked for spark and noticed some spark 'gaps' or 'misses' after checking a couple of the wires. I removed the distributor and rotor and they looked pretty bad. The rotor 'blade' is pitted and looks like it was dragged sideways across an asphalt road. The contact points inside the cap all looked badly worn too.

Simply put, I haven't fixed it yet, but I clearly don't have reliable electrical contact or 'fire'.

I'll let you all know what happens after I replace these items.