Real customer reviews from Scion owners like you.
The spark plugs are an important part of the ignition system. When you turn the ignition key (car's key) on, it causes the ignition coil to generate the spark which ignites the air-fuel mixture in the engine cylinders to start the engine. The number of spark plugs in the car is the same as the number of cylinders, although some vehicle manufacturers will use two spark plugs per cylinder. Over time, the spark plugs wear out and require replacement. When the spark plugs wear out, it is harder for it the air-fuel mixture to ignite, resulting in engine misfires. If one of the spark plugs has failed, the car will still start and run, but it will run poorly. On some vehicles, spark plug replacement may be labor intensive and involve removal of the intake plenum.