Posted on 11/28/2025
Healthy spark plugs and coils keep starts quick, idle smooth, and power consistent. They also protect the catalytic converter by preventing misfires that dump raw fuel into the exhaust. Replacement timing depends on the plug design, your driving, and how the engine is running day to day. Why Plugs and Coils Are So Important Spark plugs ignite the air-fuel mixture thousands of times per minute. Ignition coils transform battery voltage into the high voltage needed to jump the plug gap. When either one weakens, combustion becomes inconsistent, which shows up as hesitation, shaking, and poorer fuel economy. Left long enough, misfires overheat the converter and can trigger a flashing check engine light. Typical Replacement Intervals Many modern engines use long life iridium or platinum plugs that last 60,000 to 100,000 miles, sometimes more ... read more