Reading a spark plug is a great way to check your engine's health. Mechanics often read spark plugs to diagnose fuel mixture, ignition, and engine condition. Here's a clear guide for A Burnt Spark Plug: How Do I Know Symptoms? What are Common Symptoms of a Bad Spark Plug? What are the Symptoms of Bad Spark Plugs? Tom Kadlec Kia Tell tale signs your Spark Plugs are failing Wilco Motosave Your Spark Plug Speaks. Do You Listen? A simple spark plug inspection can reveal a lot about your engine's health. The color and condition of your spark plugs help diagnose fuel