From candles depends primarily on the quality launch engine. Their condition has an impact on the stability of the car at idle. If there is a failure of the candles, it can also deny other elements of the ignition system. It is also worth noting that can break the catalytic Converter the exhaust gases. It has a high cost. Faulty spark you need to "calculate" and replace. It is recommended to use spark plugs recommended by the manufacturer. If you are not able to buy analogs, it is necessary when choosing to comply with two basic rules. New plugs should be in their form close to original. They must also have close thermal characteristics. These characteristics are basic. Heat rating describes the degree of conductivity of the spark plug. It is not recommended to install on the automobile candles, which have shortened the threaded part. The fact that they quickly become clogged with sludge and become unusable.Note, in operation the gap between electrodes will increase by 0.015 mm for every 1,000 km. That is why it is best every 5,000 km to accomplish THAT. Most manufacturers recommends to replace the plugs every 30000 km. When buying always check them in the store. Some manufacturers provide warranty on these products. On many Japanese vehicles are equipped with candles that have an original design. For example, a frequently used design, with three side electrodes, or even do not have them. Keep in mind, a three-electrode spark has drawbacks. The fact that the formation of a spark which could penetrate the gap, which has the least resistance.