The arc created by the Volkswagen spark plug is why your vehicle can be propelled down the road in an efficient manner. This small electrical component is present in each of the cylinders in your engine. On older Volkswagen models, the spark plug receives its electrical current from a distributor. On the new models with electronic ignition, the origin of the current is the onboard computer. Regardless of the source of the electrical current, the arc accomplishes the same task of igniting the air and fuel mixture in the combustion chamber of your vehicle. The spark plugs are an electrical component that will wear out over time, but this wear is not like other electrical components on your Volkswagen. They will not simply burn out or short circuit, they tend to get fouled which is why they can no longer produce a spark. The electrode to which the arc of electricity jumps to at the end of the plug also disintegrates over the long time it is used. This increases the gap of the spark plug causes a weaker arc of electrical current to be created. Another way the Volkswagen spark plug might not be capable of functioning is if there is a problem with it. The only known problem that can occur is if the ceramic casing that separates the two ends of the plug is damaged in any way. The most common way for this section of ceramic to be damaged is if the spark plug is dropped before it is placed in the engine of your Volkswagen. This can create a crack in the ceramic that will prevent the flow of electricity from one end of the plug to the other causing it to be faulty.