Running Rich: Final Edition?

I've determined the cause of many of my problems, including the backfiring, tachometer fluctuation, weak cold-weather starting, cold-weather cold-start misfiring, occasional idle droop, and idle droop in frequency with turn signals.

All these issues disappear when I tighten my alternator belt. That's right. Tighten my alternator belt.

Though that belt slackens rather quickly, and it's kind of dismaying. I'm guessing either the crank pulley or water pump is bad, causing the pulley to wobble and putting extra stress on the belt. So it stretches, and I have to re-tighten it. Annoying. I'm waiting for when I rebuild the engine to replace these two things.