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Most vehicles on the road today are equipped with spark plugs. Changing your vehicle's spark plugs at the appropriate mileage intervals is an important part of keeping your vehicle operating efficiently. Most spark plugs are relatively inexpensive and can be properly installed by novice to intermediate level DIY'ers.



What is it?

  • A spark plug is a device used in a gas fueled internal combustion engine. It is threaded into the cylinder head and its tip protrudes into the combustion chamber.
  • Its purpose is to create a spark to ignite the air/fuel mixture that keeps the engine running.

How Does It Work?

  • A spark plug channels the energy from your vehicle's ignition coil across an air gap in the combustion chamber.
  • This spark ignites the compressed fuel/air mixture within each cylinder and the resulting combustion initiates the engines power stroke.

How Is It Made?

  • A spark plug is made up of a center electrode, ground electrode, resistor (in most cases) and a terminal stud that are assembled inside a ceramic insulator.
  • This insulator assembly is then inserted into a steel shell that is designed to thread into the cylinder head.

Why Does It Fail?

  • Electrode Erosion.
  • Fouling.
  • Resistor Burnout.
  • Material Failure.

What are Symptoms of Failure?

  • Check Engine Light.
  • Misfire.
  • Hesitation.
  • Hard Starting.

What Are the Consequences of Failure?

  • Poor Fuel Economy.
  • Poor Engine Performance.
  • Dead Cylinder(s).
  • Engine Damage.

If you have questions or concerns about spark plugs or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.