Unfortunately there was no "final fix" on it. I took off the valve cover and re-hooked everything up. Somewhere in there, it fixed what was wrong. I have to imagine that it was some sort of vacuum leak, although even after sealing the IACV hoses it still acted up. Since removing the valve cover, it has been running fine, passed inspection and driven a few hundred miles
I'm just as baffled as everyone else. I have to imagine it was vacuum related although there were electrical connections here and there that I had to unplug and reconnect. I'd feel more comfortable if I replaced something and it started running perfectly again but eh...guess that's the way these older cars work sometimes! Makes sense since gasoline engines pull the most vacuum at idle and under load at low RPMs so if there was a leak there would be unmetered air entering and it would lean out. Duty cycle values were fine though....weird.