The Porsche spark plug's arc at the correct time and voltage is what ignites the air and fuel mixture in the cylinders of this German sports car. This is the ignition component that is where the action takes place so this vehicle can be propelled down the road when the owner desires it. With a spark plug creating an arc in each cylinder between 2,000 to 8,000 times a minute, the engine can produce the power desired by the Porsche owner. The arc is created by an electrical current that enters the Porsche spark plug at the top end and is shot through the hollow ceramic material that channels it to the bottom electrode. There it arcs to the probe that is grounded to the engine. This is how all spark plugs function. Circumstances that interfere with this function can include the fouling of the end of the spark plug with oil or excessive fuel. The excessive fuel is when your Porsche is flooded out when it fails to start but fuel continues to enter the combustion chamber. The oil is generally from a leaking valve seal or worn out piston rings. The ceramic cylinder that the electrical current jumps through is another place that could cause the plug to fail. This is a sealed compartment in the plug. If a hair line crack is created in it for any reason, the current will not flow through it and the plug will be faulty. The only time this can occur is when a new set of spark plugs are being installed in your Porsche engine and one of them is dropped on a hard surface. If that does occur it will have to be immediately replaced for the engine to ever run smoothly.