When choosing a plug the heat range must be carefully selected for proper spark plug performance. The two most common causes of spark plug problems are carbon fouling and overheating.
Carbon fouling can happen if you do continuous low speed driving, short trips, the air-fuel mixture is too rich, or lowered compression due to wear.
Overheating results in accelerated electrode wear and can cause pre-ignition.
Choose a hotter plug if you experience carbon fouling (the lower the number, the hotter the plug). Otherwise we recommend standard temperature plugs to avoid overheating.