when in doubt OHM it out... would need osciliscope to see the firing line. cylinder inhibitor ( shorts out cylinder ) could find a miss. 50-100 rpm drop per cyl is nominal. when I took an auto class, we had a osciliscope that had an inhibitor function, would kill the cyl's automaticly and create a balance percentage. hooked it up to a junker tempo ( was sombody's car tho ), ran the test like 5 times, almost killed the motor.