[Dirty Harry]

I had a misfire problem that I was struggling to diagnose. As it turns out, the metal base on my big oval air cleaner had rubbed on one of the wire boots on the distributor cap to the degree that that wire was shorting to ground. The underside of the air cleaner base had a burn mark from where the spark had arced. That's not something you might normally think of, so I pass this on to, hopefully, save someone the difficult diagnostic path I had to take.