Help with a miss and voltage drop

The reason I have the curb idle so high is to help keep the headlights from strobing at stop signs. But I am going to try to retime it again, and then adjust the carb. and then replace the ICM. My main confusion is trying to understand why when I hear the miss, I see a big voltage drop (1v). Is it cause and effect?? is it dropping the voltage because it missed? Or is is missing because the voltage dropped?