So I tore the engine down to the rotor and cap. Tested all my plug wires - all gave me readings from 410 - 630 ohms - no outliers. Took the cap and rotor off - cleaned up all the contacts with a wire brush on a dremel so they're nice and clean now. Made absolutely sure all the plugs were seated strongly in the cap. Re-assembled and no change. Swapped fuel pumps (even though fuel pressure was good) - no change.
Fuel pressures are all good. Plug wires all have consistent ohm readings. Cap and rotor contacts have now been cleaned. Sounds like fuel and ignition system check out pretty well.
I did an old-school trick where you put a dollar bill over your exhaust while the car is running. If everything is all pretty good with your engine, the dollar bill should not try to enter the exhaust pipe. As the car was running, the exhaust did try to suck the dollar back into the pipe....