I replaced the fuel filter and tightened all my grounds (the valve cover to coil was a bit loose) and it now runs great. My working theory is this: when low on gas, the pump picked up sediment, clogging the filter. With the filter clogged, fuel delivery obviously was poor, causing a misfire, loosening an already iffy ground.
I also swapped the battery for my spare. My idle isn’t even lopey anymore. I’m also getting better fuel economy. Today was a good day. Now I just need to do timing, PCV, fuel pressure regulator, get a real exhaust, replace front O2 sensor, get a hawg ass cam, put a chip in the ECU, clean up some rust, and I'll be ready for winter.