Posted under Engine

Though they may be tiny, spark plugs play a huge role in how your car performs. It’s important to make sure your plugs are working the way they should, because without them, you can forget about even getting your car started. They are integral in providing the necessary spark of electricity to the combustion chamber of your engine. 

Your engine’s plugs should be clean, and the electrodes should be free from any damage. A dirty spark plug can do a number on your engine’s performance. If your spark plugs are covered with motor oil, fuel, or carbon—or if they’re blistered from your engine’s heat—they are considered defective and should be replaced. Operating your vehicle with fouled spark plugs can cause several problems so it’s best to take care of the issue the moment you experience bad spark plug symptoms.


You may be asking, “How do I know if my spark plugs are bad?” Well, we’ve compiled a list of bad spark plug symptoms, to help you determine whether your spark plugs need to be cleaned, repaired or replaced.

Reduced Fuel Economy

Are you stopping for gas more than normal? More trips to the gas pump could be the result of dirty or fouled spark plugs. Dirty spark plugs will guzzle more gas that clean ones, so it’s best to keep those plugs in tip top shape.

Lack of Acceleration

When a spark plug becomes worn down, fouled up, or dirty, it won’t spark your engine effectively, and your car will lose a lot of its get-up-and-go. If your car feels sluggish, your spark plugs may be the reason why.

Hard Starts

If you’re having issues getting your car started, one reason may be defective spark plugs. If your battery is working, and your tank is full, then more times than not the issue stems from your spark plugs not sparking the way they should.

Engine Misfire

Engine misfiring? If you sense that your engine is struggling when you start it, or stutters while running, chances are faulty spark plugs are to blame. Even the slightest interruption in your engine’s combustion process will cause your car’s performance to drop significantly. 

Rough Idle

Feel that? If your car is shaking or vibrating while it’s sitting idle, then your spark plugs may need to get checked out. A fouled spark plug can make your engine sound choppy to the point where the entire car may shake. If that’s the case, head on over to your nearest Jiffy Lube® before things get worse.


Most problems that are the result of defective, fouled or worn spark plugs can be taken care of quickly and easily with the help of a trained Jiffy Lube technician. Consistent spark plug maintenance will help ensure that your car’s ignition system is up to snuff. When visiting a Jiffy Lube location, technicians go above and beyond in restoring your spark plugs in the case that they need to be replaced, adhering to your vehicle’s Original Equipment Manufacturer’s (OEM) specifications. So the next time you’re experiencing any bad spark plug symptoms, you can rest assured a Jiffy Lube technician will take care of your car, getting you back on the road quickly. 


Jiffy Lube technician talking to a woman about her vehicle's spark plugs


Now that you have a better understanding of your spark plugs, you can learn more about other components of your car by visiting the Jiffy Lube Resource Center. New content is added regularly, so you can come back to the site to answer any questions about your vehicle. 

Please note: Not all services are offered at each Jiffy Lube location. Please check with your local Jiffy Lube service center or visit for specific services offered.