If you were doing a cylinder balance test on a vehicle with DIS
ignition, pulling one plug-wire would kill two cylinders?

But, as long as you used a spark tester, the companion cylinder would
still fire.

I guess you would have to kill the engine everytime you changed plug
wires and restart. I wouldn't want to handle the wire with the engine
running, I tried that before, that stuff has a bite to it. I was even
holding an insulated screwdriver handle, still got me. I was dancing a
jig hollering at the helper to turn the key off. The vehicle was OBD1.
thanks