Sudden loss of power

Ok, I done figured it out. And, of course, it was a quick and easy fix -- you know, the kind that always get overlooked because "it can't be something stupid like that"?

I had a bad chassis ground.

I had been fiddling with the heater hoses the other day, and apparently pulled one of them just loose enough that an ever-so-slight drip was coming out of one ... right onto a ground to the chassis. I unhooked the ground, scrubbed it with a steel brush, slammed it with dielectric grease and re-attached it. Then, I tightened up my heater hose. Problem solved!