All About Spark Plugs

When you think of vehicle maintenance, what is the first thing you think of? Oil changes and brake checks are probably at the top of your list, but, how often do you think of the spark plugs?


Spark plugs play an important role in the health of your engine. They can affect your fuel economy, the amount of power put out by the engine, and how efficiently your engine runs. Like the oil and brakes, spark plugs need to be maintained and changed when necessary.

What are spark plugs?

Spark plugs are an integral part of the ignition system. Put simply, spark plugs provide the spark needed to ignite the combustion and start your vehicle. Without properly functioning spark plugs your vehicle will struggle to start. Or, worse, not start at all.
The number of spark plugs your vehicle has depends on what cylinder engine it has. If your vehicle has a six-cylinder engine, you will have six spark plugs. The spark plugs can be found screwed into the top of each of the cylinders where they receive an electrical current from the ignition coils creating the spark that ignites the air-fuel mixture in the combustion chamber. Spark plugs are also responsible for transferring heat away from the combustion chamber. Each time you operate your vehicle, these events take place hundreds of times per minute to keep your vehicle moving.

When do spark plugs need to be replaced?

Like your oil and brakes, your spark plugs will need to be replaced; however, not nearly as often. A common recommendation for spark plug replacement is every 30,000 miles. There are, however, high-performance spark plugs that can last up to 100,000 miles. You should look in your owner’s manual to find your vehicle’s specific recommendations. Also, keep in mind that when it is time to replace your spark plugs the same kind that was used in your vehicle when it was manufactured is the kind that should be used again.
Spark plugs may last longer than other parts of your vehicle, but they don’t last forever. If you are driving a vehicle with a lot of miles, or if you find that your engine is running rougher than normal and/or you have lost fuel economy it may be time to check or replace the spark plugs.

These are four signs that it is time for a spark plug change:

You can hear it. If you are hearing a pinging, knocking, or rattling type noise it may be indicative of spark plug misfire. Your engines pistons move at high speeds, if the spark plug is firing at the wrong time it will create strange noises from the force of the combustion and pistons not operating properly.
You have trouble starting your vehicle. Your vehicle’s ignition system works harder when the spark plugs are worn. This symptom becomes worse in harsh weather conditions. If you find that your vehicle is having trouble starting or feels jumpy and spasmodic then you may want to check the spark plugs.
Poor vehicle performance. When spark plugs are worn and in need of replacing you may notice that you have weak acceleration and/or a rough idle. When you have weak acceleration, it will feel like your vehicle is working extra hard to move. With a rough idle, you may feel vibrations throughout your vehicle when your engine is running, yet stationary- like at a stoplight. Ignoring these symptoms can result in costly damage to your vehicle, so, have it inspected right away.
Decreased fuel economy. Spark plugs help to keep emissions coming from your vehicle at a minimum. When they have gone bad, they cannot properly complete combustion and waste fuel. If you find that you need to fill your gas tank more than usual, you may want to check your spark plugs.

Having healthy spark plugs is important to your vehicle’s ability to start and remain powered as you drive. If you experience any of the above symptoms don’t hesitate to bring your vehicle to the experts at Accurate Service for an inspection. At Accurate Service we have over 20 years of auto repair experience. From Ford to Audi to Honda, we work on all makes and models of vehicles. Call 520.441.4744 or schedule your appointment online.