For something that's smaller than your pinky finger, spark plugs have a ridiculously important job: they create a spark that ignites the fuel-air mixture inside your engine's combustion chamber. But ...

Dear Tom and Ray, I'm wondering if you have any firsthand experience with the latest in spark-plug technology, the not-yet-famous "Iridium" spark plug. The Iridium plugs are supposed to be more ...

Gas-powered internal combustion engines need spark plugs to (literally) ignite and complete the combustion stroke, enabling the motor to produce power. They may seem unusual to the untrained eye, but ...

How long spark plugs last varies with different cars and different types of spark plugs. Older cars often had to have their spark plugs replaced every 5,000 to 10,000 miles, while some newer cars — ...

Tom: We think it's good that you're not expecting improved performance. And you'd do well to not expect anything in the way of gas mileage or power delivery either (whatever that means). Tom: The ...

Baseline: Internally stock Bullitt 4.6 GT with Vortech supercharger, Vortech aftercooler, and 8 pounds of boost Spark Plugs: Engine as in Baseline, but with Denso IT20 Iridium spark plugs Exhaust: ...