Posted under Car Engine

How can something so small play such a big role in a vehicle? Well, that’s what a spark plug does, as this little part ignites the air/fuel mixture within the engine's combustion chamber. In other words, it provides the literal "spark" that starts the engine.

But like most vehicle parts, spark plugs eventually need replacing. The electrodes on each plug slowly wear down until they can't produce a spark anymore. It's normal wear and tear, but it can cause your engine to perform worse without you even realizing it. That’s why you should pay close attention to your vehicle and watch out for the following symptoms.

How to Check If Spark Plugs Are Bad: 6 Signs to Look Out For

1. Check Engine Light Illuminates
When the dreaded Check Engine Light (CEL) pops up on your dashboard, it could mean many things — and faulty spark plugs are no exception. In some cases, the CEL may start flashing, indicating catastrophic engine misfires could be happening. Whether the CEL is static or blinking, take your vehicle to your nearest automotive professional as soon as possible.

2. Starting Problems
As mentioned earlier, spark plugs are essential to starting your engine. When spark plugs wear out, they may struggle to produce a strong spark to ignite the air/fuel mixture, resulting in extended cranking or multiple attempts to start the engine. Also, pay attention to any unusual hesitations or sputtering while driving. If you encounter any of these symptoms and have a working battery and full gas tank, your spark plugs might be defective.

3. Engine Misfires
An engine misfire can occur when the spark plugs fail to ignite the air/fuel mixture at the right time. So, what happens next? You could notice a lack of power, hesitation, or jerking sensation while driving around town. To avoid further damage to your vehicle, get your spark plugs inspected and replaced if necessary. It's better to be safe than sorry!

4. Poor Fuel Economy
Are you hitting the gas pump more often than usual? Worn or fouled spark plugs can cause the engine to misfire, increasing fuel consumption. So, if you notice a drop in your vehicle’s gas mileage, it’s worth looking at your spark plugs.

5. Acceleration Problems
Faulty spark plugs can cause a delay in power delivery, leading to sluggish acceleration and reduced engine response. If your vehicle's acceleration and overall performance are not up to par, it might be time to replace your spark plugs.

6. Rough Engine Idling
Feeling some shaking or vibrations while your vehicle is sitting idle? You may need to inspect your spark plugs because these little guys can make your engine sound and feel choppy to the point where the whole vehicle might shake. A normal idle should be smooth and quiet, so if you’re experiencing any engine knocking or rattling, your spark plugs may be defective.

Technician waving goodbye to customer after having their spark plugs replaced.

Think You Need a Replacement? Visit Your Local Jiffy Lube

Driving with bad spark plugs can wreak havoc on your engine. So don’t delay service! Bring your vehicle to your local Jiffy Lube®. Our trained technicians will remove and replace your spark plugs and inspect your ignition system based on your vehicle manufacturer's specifications. They can also evaluate your vehicle and suggest a maintenance schedule based on Original Equipment Manufacturer (OEM) recommendations.

When you come to Jiffy Lube for regular maintenance, you can reap the benefits of changing spark plugs, including: 

  • Better fuel economy
  • Smoother starts
  • Improved overall engine performance.

NOTE: Not all services are offered at all Jiffy Lube service centers. Please call ahead or check to ensure the service is available at the Jiffy Lube location near you.