Posted on 1/30/2026
This question usually comes up right after someone gets hit with a quote or right after a misfire. Spark plugs are normal maintenance, but ignition coils feel more like a repair, so it’s natural to wonder if you should just do everything at once and be done with it. Sometimes that’s the smartest move. Other times, it’s unnecessary money up front. The right answer depends on mileage, symptoms, and how the car has been maintained. What Each Part Does And Why They Get Blamed Together Spark plugs ignite the air and fuel in each cylinder. Ignition coils provide the high voltage that makes that spark happen. On most modern engines, each cylinder has its own coil, sitting right above the plug. Because they work as a pair, one weak component can make the other work harder. Worn plugs can increase the gap and make it harder to fire the spark. That extra demand can stress coils over time. A weak coil can cause incomplete combustion, leaving deposits on the ... read more