Resistor Spark Plugs
Resistor type spark plug’s incorporate an internal resistor to suppress ignition noise generated during sparking. The ignition noise which is often known as either electromagnetic interference
As EMI or RFI can also cause premature failure to other electronic components in a modern vehicle, it is important that resistor spark plugs are used to prevent this possibility.
Put simply, when a spark is formed it creates a mini-earthquake in the electronic world; the internal resistor in a spark plug filters out the noise created that may affect electrical components.