In skimming back through this thread, I didn't find anyone else's log showing timing (but I probably skimmed right over some, sorry about that). I wonder if anyone who has looked at these things can say if the logged timing data I'm seeing is typical. Looks like odd behavior to my untrained eyes.
The log below is with the car at ~190°F, stationary and in neutral (manual trans). Idle is lumpy but steady at 750 RPM, then starts misfiring more sharply when I bring the revs up slightly. Timing is bouncing around during the former, then sets dead even during the latter. What gives?
I'm lining up for some more diagnosis this weekend: swap coil packs, check plugs, compression test, test crank position sensor, check for vac leaks. I'll likely run a can of seafoam through the manifold for good measure.