What Are Spark Plugs?

Having uncertainty around anything regarding your vehicle doesn’t feel great. When you think about spark plug wires, do your anxiety levels start to rise? Do you know what it looks like when one goes bad?

Whether you’re tired of replacing them or don’t know what a spark plug socket looks like, this post has something to offer.

This post contains the essentials everyone should know about spark plugs. Continue reading to learn what they do, what can go wrong, and which options you may want to purchase in the future to prevent problems. 

Spark Plugs 101: What Do They Do?

Spark plugs give your car the ignition it needs to ignite the air and fuel mixture in your engine. The engine contains valves with cylinders that create a series of small explosions. The fuel-to-air ratio allows this to happen, but it needs a spark of electricity to get started. 

This series of internal combustion turns the crankshaft inside the engine and gives power to the vehicle. Without a spark plug, however, the process can’t start, and your car remains stationary. 

What Is a Spark Plug Gap?

Spark plugs need a gap between the center and the electrodes to work. If this distance isn’t precise, the arcs it produces may not produce the desired voltage.

The correct distance for the gap is in the owner’s manual. If you notice burn marks around the electrodes, that can be a sign that this is happening. You also may have a clicking or knocking noise coming from the engine due to misfires.

What Types of Spark Plugs Can You Buy?

Other than materials, the primary differences between spark plugs are the amount of voltage required. The general rule is that less voltage needed to create a spark means a more efficient ignition system.


Copper cores with a nickel alloy require the most amount of voltage to generate a spark. Nickel is not a durable material, so you’ll find yourself replacing these more frequently than others. These may be inexpensive, but by the time you’ve replaced them enough times, those savings become negligible. 

Single Platinum

This type of spark plug is similar to the others, but its electrode is a platinum disc welded to the tip. Since this generates more heat, they tend to resist carbon buildup. With an estimated lifespan of 100,000 miles, these also have a heftier price than other options.

Double Platinum

You’ll typically find double platinum in wasted spark systems. That process means that the ignition for two coils happens simultaneously, but one air-fuel mixture doesn’t ignite. That makes this choice more reliable, but that type of quality comes with eye-opening prices.


Iridium is a more durable material that offers a much longer lifespan. The center electrode is smaller, which means less voltage is required to create a spark. With these advantages in mind, it’s also critical to understand that these come with a higher price tag.

Silver Spark Plugs

You won’t find these as often because they don’t last as long as others on the list. This type of spark plug is more commonly associated with European motorcycles or cars. They have excellent thermal conductivity, but that also means sacrificing durability.

How Do Spark Plugs Go Bad?

Age is the most common reason you get a bad spark plug, but that’s not the entire story. 

After creating an arc that ignites the fuel and air mixture inside your engine enough times, the electrodes begin to degrade. Each spark removes a certain amount of metal, and after that happens enough, it won’t arc electricity anymore.

This scenario assumes that we’re considering a spark plug in an engine that received regular maintenance. Other reasons your car won’t start or sputters include the following:


Carbon tends to buildup on the tip of spark plugs over time and causes failure. Clogged air filters or dirty injectors tend to make this happen if they’re left unattended, especially on spark plug wires. 


It’s not uncommon for oil to seep and find its way into a combustion chamber. If this gets onto the spark plug, that can ruin the tip and prevent it from arcing electricity. 


If the electrodes overheat on a spark plug, they tend to wear out fast. Improper air to fuel ratios or poorly timed engines can cause this problem to occur.

How Can You Tell If a Spark Plug Is Going Bad?

As a spark plug starts to fail, there are signs that you can look for to understand the problem. You may experience a rough idle, slow acceleration, hard starting, or high fuel consumption.

A rough idle occurs when you hear rattling noises coming from the engine while your vehicle is parked. If a spark plug is worn, it can cause this type of effect to happen when you’re motionless.

Slow acceleration can happen due to a dirty spark plug that isn’t operating the right way. You may experience your engine stops or stalls followed by a struggle to start again. 

A spark plug that doesn’t work can cause significantly more fuel consumption also. If things don’t arc properly during the ignition process, you can burn more gasoline in a much faster time period. Using more gas than usual doesn’t mean that this is the problem, but it can be a symptom in new or used cars

More About Spark Plugs

This information about spark plugs gives you the essentials, but it’s natural to have more questions. Understanding what options exist and why the problems occur doesn’t complete the picture for everyone.

It’s easy to become frustrated while having difficulty troubleshooting an ignition problem in your vehicle. Contact us today, and one of our experts will connect you with a solution.

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