The days of changing your spark plugs every couple of years are over. Back in the day, spark plugs truly did wear out that often! A couple of factors have changed that for the better. First, spark plugs are made of better materials that are designed to last longer. Second, modern engine controls have reduced the amount of carbon deposit emitted from fuel that isn’t burned properly and completely. These deposits used to build up on spark plugs and ruin them.
Engine control computers precisely time when fuel is injected into the engine and when spark plugs fire. Unless something is already wrong with your car, spark plugs don’t just fail like they used to. Electricity from the battery goes into a coil that allows power to build up anywhere from 12,000 to 45,000 volts, depending on the vehicle. The engine management computer tells the coil when to release the power into the spark plug. The electricity then travels through a wire from the coil to the spark plug. At the tip of the plug, a spark jumps between two electrodes and ignites the gas in the combustion chamber.
Some engines have more than one coil. Coils wear out and need to be replaced from time to time. Spark plugs can also wear out. Modern engines are delivering more power and fuel economy than ever before. This is largely credited to fast engine control computers, advanced sensors, electronic ignition and improvements to the spark plug.
One last thought: it is critically important to have the right kind of spark plug for your vehicle. Engines are designed to run with different internal temperatures, so spark plugs have different designs to work within those internal temperatures. Your service advisor will be able to get the right plugs for your vehicle and will be able to advise you on when you should replace your spark plugs as well!