i have a vague memory of either my dad or grandfather working on a car and holding on to a sparkplug to see if it not firing was the cause of the problem. I rem

i have a vague memory of either my dad or grandfather working on a car and holding on to a sparkplug to see if it not firing was the cause of the problem. I remember them dropping it and shaking their hands like they touched something hot and saying "no, that's not it" hah.