I had a general post about trying to figure out a problem like we used to do it before computers.
Well, things do change.
If you like, you can also replace the fuel filter, points, plugs and condenser every 12 months or 12,000 miles, and be sure to replace the rotor every other minor tune-up. Wires and distributor cap should go to 36,000 miles. If you use a good fuel treatment and buy gas at a reputable station you can probably go 75,000 miles before the carburetor needs to be rebuilt.
Go back a few generations and be a doctor. No diagnostics to speak of, if there's something internal going on you can't hear with a stethoscope, hack them open for "exploratory surgery." Now you've got all manner of diagnostics available to reduce or eliminate guesswork.
Really, sooner or later you'll have to face it. You are driving a computer (well, several of them actually) on wheels. If you want to approach it with your stone axe, well, so be it. But hopefully you'll admit that it's a losing battle.
Guessing at a potential problem when you get a CEL quickly becomes time-consuming, frustrating and expensive. Why not avail yourself of technology? Otherwise,you may as well dump this problem child and go buy a 1965 Dodge Dart
and be done with it.