I agree, I am trying to trouble shoot a problem with my ignition. I have taking out the plug and turned over the engine and the the plugs, but not all the time and sometimes only one plug will fire and not always the same one. That is why I am looking for the technical background on the ignition. I what to figure out if the sensor is bad or the magnet or ignition box. I don't want to have to buy the hole system if only one part is bad.