won't start most of the time, but occasionally starts... runs poorly (misses badly), won't take throttle hardly at all, but will tend to stay running (idling) once it does start (although it runs lumpy--due to missing, i presume. Pulling number 4 plug wire actually makes it run BETTER when it's idling.) The spark is intermittent and usually weak, when it DOES fire (this observed upon cranking w/ one plug out at a time. After some cranking and not starting, the plugs are wet with gas, so it seems to be getting fuel.
Plugs are nearly new, new plug wires, distributor cap & rotor. Coil OK (makes good spark from coil wire to body ground). Have checked the (mechanical) timing repeatedly and it looks fine.

I'm starting to suspect something like the transistor switching unit or trigger unit in the distributor (although i don't know exactly what these are).

Any help would be appreciated.