What Are the Signs of a Bad Spark Plug?

Spark plugs ignite the air-fuel mixture in the engine. When they wear out, engine performance declines significantly.

Common Signs

  • Engine misfires
  • Rough idling
  • Poor fuel economy
  • Difficulty starting
  • Reduced acceleration
  • Check engine light

Why Replacement Matters

Faulty spark plugs force the ignition system to work harder and can eventually damage ignition coils and catalytic converters.