It is the arc from the Infiniti Spark Plug that ignites the air and fuel mixture so your power plant can produce the explosion necessary for the propulsion of your vehicle. There is an individual spark plug for each cylinder on your Infiniti engine supplying this electrical arc.
The spark plug is constructed with metal ends but is hollow in the middle. The arc is created by the electrical impulse jumping from one end of the plug to the other. The center section of the Infiniti spark plug is made from ceramic. This is a non-conductive material so the charge can pass through it without it being redirected or becoming grounded out.
A faulty spark plug can occur when the tip, where the electrode is that goes into the cylinder becomes fouled out by being covered with fuel or oil. In time the electrode will also wear out from the numerous times an arc is generated. This is the most common reason given for the need of a new set of plugs in your Infiniti engine.
The area between the electrode and the center core of the spark plug at the end in the combustion chamber is called the gap. This gap has to be the correct distance so the strength of the arc passing between them is at the correct power level.
If the Infiniti owner does their own tune-up which includes replacing the spark plugs there is one precaution that should be taken. The ceramic center of the plug is very fragile and if the plug is dropped for any reason from any height, it should be replaced. Even a small crack in this section of the plug will cause it to become faulty.