The main fail part on these ignitions is the little spring connector between the resistor and the spark plug tower. This connector spring is part of the resistor boot under each coil. The resistor itself and the top coil connector are usually fine. But the bottom connecting spring fatigues from both the heat that is trapped at the plug BC this cavity is encased by the coil and it is simply a compression contact. Not the best electrical connection, but BC the coil is on top , that is the design they used.
Once the spring looses its tension , the connection becomes weak [ as it is simply a compression contact].
Results are mis-fire at that plug, plus a possible mis-fire at the
other plug due to this being a series coil circuit. [ If the spark jumps to ground at this weak connection, the other plug will fire, however]
The other 3 resistors do not have this problem as they have a snap connector at both the plug end and the coil end and the plug cavities are open to some cooling.
So , mostly. you can rectify the mis-fire conditions on these by simply replacing the resistor boot connector under each coil.
About $7 ea..........