Understanding a vehicle’s inner workings and maintenance needs can be a game-changer for anyone who owns it. A component that often goes unnoticed, but plays a pivotal role in the smooth functioning of your car, is the spark plug.

What are spark plugs and how do they work?

Spark plugs are crucial components in a car’s ignition system. They’re responsible for igniting the air-fuel mixture within the combustion chambers. When the ignition coil sends a high-voltage electrical current to the spark plug, it creates a spark that ignites the mixture, providing the necessary energy to power the engine. Without functional spark plugs, your car would not start.

Here are the signs you need to look for indicating that your car’s spark plugs might need to be replaced!

1 Difficulty Starting

Your car has difficulty starting

If you need to turn the ignition multiple times (or push the start button more than once) before the engine roars to life, worn-out spark plugs might be to blame. Faulty or warn-out plugs can’t generate the spark needed, making it difficult to ignite the air-fuel mixture. Over time, the prolonged strain on the ignition system can lead to additional damage. Inspecting and replacing the spark plugs can ensure your car starts promptly, saving the battery and other components from undue stress.

2 Rough Idiling

Your engine is idling rough

A smooth idling engine is a sign of good health. However, if you notice a rough, vibrating idle, it’s often an indication that the spark plugs are deteriorating and not firing correctly. This inconsistency in spark can disturb the engine’s rhythm. Not only is this unsettling for the driver, but it can also cause wear on the engine components over time.

3 Missfire

Your car is misfiring

Engine misfires are hard to ignore. They can lead to decreased performance, higher emissions, and even damage to the engine. Worn or fouled spark plugs often misfire, causing interruptions in the engine’s power delivery. Regular misfiring can harm the engine’s health, increase fuel consumption, and potentially lead to more costly repairs.

4 Fuel Consumption

Your fuel consumption has increased

Old or damaged spark plugs lose their efficiency. When this happens, they can’t burn fuel efficiently, increasing consumption. If you notice you’re visiting the petrol station more frequently, it’s worth checking those plugs. Inefficient combustion hits your wallet and increases the vehicle’s carbon footprint – not ideal for the environment.

5 Car Accelerate

Your car doesn’t accelerate like it used to

Remember the thrill when your car responded instantaneously to the throttle? If your vehicle feels sluggish and doesn’t pick up speed as swiftly, your spark plugs might be crying out for a replacement. Degraded spark plugs can hinder the engine’s ability to burn fuel efficiently, resulting in a loss of power. This lack of responsiveness can be especially concerning when overtaking or entering highways.

6 Noise

The engine is noisier than normal

While engines aren’t whisper-quiet, an unusual rattle or knocking sound can signify worn-out spark plugs. These sounds stem from pre-ignition, where the air-fuel mixture in the cylinders detonates prematurely due to the deteriorating plugs. Continuous knocking can lead to more profound issues, like damaging the pistons or cylinders, which are expensive to fix.

7 Engine Warning

The engine warning light is on

Modern cars come equipped with a plethora of sensors. If there’s an issue with your spark plugs or any related component, the engine warning light on your dashboard might illuminate. Though this could signal various issues, it’s always wise to check it. Ignoring this light, especially if caused by a spark plug issue, can result in decreased performance and increased fuel consumption. Always treat an illuminated engine light as a prompt to consult a professional.


Spark plugs might be small, but their role in your engine’s performance and efficiency is monumental. Regular checks and replacements are vital to maintaining your car’s health. And when it’s about such an integral component, why not rely on experts?

When it comes to your car, trust the experts at Sutherland Automotive. Our experienced team of mechanics is dedicated to providing quality mechanical repairs, maintenance and more. Don’t leave your vehicle’s performance to chance. Book an appointment online today