How often do you jump into your car in the morning, turn the key, and drive away to start your day without a problem? With a well-maintained vehicle, that describes almost every day. 

Yet there comes a time when you turn the key and it doesn’t feel right. Maybe it takes a while for the engine to turn over. Or maybe you hear no sound at all. 

What is it?

While most immediately think it might be the battery, (it’s a good guess and is worth checking out,) it could also be your spark plugs. While you don’t have to change your spark plugs the way you do motor oil or an air filter, spark plugs can and do wear out over time. 

What are spark plugs?

A spark plug is a small device that plugs into the cylinder head in the engine, providing the spark for combustion between the battery and the spark plug. 

The spark plug sits at the top of the cylinder head. The piston moves down into the cylinder, taking in fuel and air. As it moves back up, it compresses the fuel and air, allowing the spark plug to spark and ignite the mixture. This gives the vehicle energy as it pushes back down, clearing out exhaust as it finishes its cycle. The process starts all over again. 

A four-cylinder car will have four pistons and four spark plugs. A six-cylinder vehicle will have six. This little tool is a reliable component that keeps on working through thousands of rotations every single time you take your car out on the road. For example, in a four-cylinder 2.0-liter engine, spark plugs will fire 200 times per minute while sitting and idling. 

Different types of spark plugs

Like other parts of your car, there are different types of spark plugs available depending on the type of engine your car has. Choosing is based on several things: how many cylinders your engine has as well as performance. 

You’ll find spark plugs at all price points, with the cheaper ones, in general, providing a shorter life span. Manufacturers will recommend which type of spark plug to use, so it’s a good idea to check your owner’s manual. Different spark plug types include:

• Copper – this has been around for decades and is the most common and economical. They also have the shortest life span of about 30,000 miles. 
  
• Iridium – provides a long life, which is also reflected in the cost. These are performance driven, so if your vehicle’s manufacturer recommends them, sticking with them will ensure your car remains in top working condition. 
  
• Platinum – one of the newer additions to the market, a platinum spark plug will typically last as long as 100,000 before needing replacement. They run hotter and reduce carbon buildup in your engine. 
  
• Double platinum – these are common in cars with “wasted spark ignition systems” where two spark plugs fire at once. This increases wear and tear on the spark plugs, and will be replaced more often than other types. 
  

When should you replace your spark plugs

If you check with your owner’s manual, the manufacturer will recommend how often you should replace the spark plugs. Use that as a guide for general upkeep and maintenance. However, your vehicle does provide other warning signs if the spark plugs start wearing down. 

Check engine light – this frequent dashboard light can signal a variety of problems inside the engine compartment. If a plug starts to fail, it will send a warning signal through the check engine light. If a spark plug doesn’t provide proper ignition, it can cause the engine to misfire. A misfiring spark can also generate rough idling, uneven power while accelerating, and a greater chance of exhaust emissions. 

Trouble starting – the spark plugs provide one of the most important jobs when you first start your car. Without the initial spark, the engine wouldn’t receive enough power to turn over and stay operational. As spark plugs wear down, they have a harder time creating that spark that powers the engine. If the engine cranks over but has difficulty trying to turn it on, it could be a problem with the spark plugs. If there’s no power at all, it’s most likely the battery. 

Rough idle – when you start to notice the engine knocking, rattling, or pinging, the spark plugs may be to blame. 

Acceleration issues – driving is something we do often enough that we have certain handling and performance expectations. If it suddenly isn’t as responsive as it once was, it’s a sign of a part wearing down to the point of eventual failure. Spark plugs can cause your vehicle to feel sluggish when you press on the gas pedal, giving you a feeling of unresponsiveness. You’ll feel like you’re stepping on the pedal harder trying to make the car go. 

Filling up at the gas station more – as spark plugs continue to wear down, it will increase fuel consumption. Spark plugs will no longer burn fuel effectively, meaning you’ll need more fuel to accomplish the same process. According to the National Institute for Automotive Service Excellence, a bad spark plugs can decrease fuel economy by up to 30 percent.

What happens if you wait too long to change your spark plugs

Can you keep putting off spark plug maintenance or replacement? Drivers do it all the time. 

But those little warning signs will continue to grow. 

It’ll take longer for the engine to turn over while you turn the key as the spark plugs have more trouble catching a spark. 

You’ll be pulling into the filling station more frequently, watching your gas efficiency plummet as more gas is needed to keep the vehicle running. 

You’ll hear more noises coming from the engine compartment as it has trouble keeping the entire system running the way that it should. 

The more stress is put on the engine compartment, the more it impacts other parts and components. What could have been an easy maintenance issue – changing the spark plugs – can accelerate into a more expensive fix. 

What’s the easiest way to keep repair costs low and keep your car in good working condition? Maintain your car on a schedule, and bring it in at the first sign of a change. 

It’s the best way to keep your car running well, there for you, whenever you decide to head out for a drive.