One of the worse shocks I ever got was from a Pontiac Fiero. My roommate's brother is dead on the side of the road, called me up to do some diagnosing. It's dark when I get there, so we can see that there is a very weak, feeble spark when I did the old pull-the-plug-and-rest-it-on-the-head trick to see if the ignition is hitting. "Hummm", young, green-as-grass stupid me thinks, "Must be a dead wire. I'll just check the other end of this plug wire..." Yup, holding the other end of the plug wire near the distributor contact results in a feeble spark, too. "Humm, must be a dead coil. Let me try pulling the coil feed." Still have a feeble spark near the distributor contact. (You can see where this is going, can't you?) "Hummm. Bad coil wire to the distributor? Lemmee try pulling the other end... OK! Crank it again... HOLEEEE-#@$^Q@$@!"
First time I'd ever found out just how much energy a modern system develops. Yeesh, big PURPLE lightning bolts from that one. My right hand was numb for a couple days.
One set 'o wires, one rotor, and he was on his way. Me? Lesson learned. Ouch!