Biggest distributor issue I find
What I am saying is is there is a deviation in timing between cylinders. Timing is typically measured on car, by using #1, but #6 one crank revolution around could be used, if it is different then that shows problem, but run out could be at different angle, and change more significant there.
The variable reluctance pickup generates a voltage signal based on change of magnetic flux with time. The flux changes due to proximity (gap) of reluctor to pickup, shape of reluctor (tooth), angular velocity (RPM), and variation of reluctor magnetic properties (rem mag, permability). The tigger point of ignition is related to signal threshold of pickup signal, in transition off tooth.