Posted on 12/19/2025
When spark plugs start wearing out, the changes are usually small at first. Maybe the engine feels a little lazier, fuel mileage is not quite what it used to be, or the idle has a slight stumble on cold mornings. Because the car still starts and drives, it is easy to ignore those early hints. Paying attention to them and replacing plugs on time can prevent bigger issues with ignition coils, catalytic converters, and drivability down the road. What Spark Plugs Do Every Time You Start The Engine Spark plugs sit at the end of each cylinder, creating the spark that ignites the air-fuel mixture. They have to fire thousands of times per minute, under high heat and pressure, without misfiring. Over time, the center electrode and ground strap wear away, the gap opens up, and deposits build on the insulator. As the gap grows, the ignition system has to work harder to jump the distance. That extra strain shows up as a weak spark, occasional misfires, or coils wor ... read more