Spark Plug Replacement

Some auto manufacturers recommend 100,000+ mile spark plug replacements; we’ve discovered that many drivers seem to believe that all cars have 100,000-mile plugs. Unfortunately, this isn’t the case! Spark plugs have become more reliable and longer lasting over the decades, and some premium spark plugs are actually designed to last up to 5 years or 100,000 miles. However, waiting too long for spark plug repair or replacement can affect the efficiency and performance of your vehicle, which is why many service intervals are significantly less—typically 30,000 miles.  

For this reason, we recommend following the spark plug replacement interval suggested by your vehicle’s manufacturer—as well as the same type of spark plugs. Using a different brand of spark plugs can cause drivability issues in some cars. It’s also important to keep your driving habits and conditions in mind when determining replacement intervals. Check your owner’s manual for the recommended service interval or ask your service advisor.

Some common signs you need spark plug repair include:

  • Difficulty starting your vehicle
  • Engine misfires
  • Poor fuel economy
  • Rough, loud idling
  • Your car struggles to accelerate
  • The check engine light is on
  • The engine sounds louder than normal

When you need spark plug replacement, visit the skilled professionals at Certified Automotive Specialists. Since 1978, we’ve prided ourselves on offering the best auto repairs and maintenance in the area. Our shop is ASE-certified and AAA-approved—we’ve also been named one of the top 10 auto repair shops in the nation by Motor Age magazine! From oil changes to engine and spark plug repair, there’s no job too big or small for our talented technicians. 

Certified Auto Specialists: the friendlier and more helpful auto shop! Feel free to call 626-963-0814 with any questions and we will be glad to help, or visit our website at

Hometown Service You Can Count On!

Ready, Aim, Misfire!

Have you ever spilled a drink at a gathering? Or worse, knocked over someone else’s? Maybe red wine on a white carpet? A party foul is sure to muck up a good time. Fouled spark plugs do the same thing.

Spark plugs are the life of your engine’s party. They get a high voltage electric current from the ignition coil(s), igniting the air-fuel mixture in the combustion chamber. When you are driving, this occurs thousands of times each minute and is what propels you down the road. They not only get the party started; they keep it rockin’!

Occasionally, spark plugs misfire when the spark is too weak to ignite fuel. This causes a temporary loss of power, wasted fuel, and pollution. Misfiring spark plugs can make your vehicle hard to start. It may also start running rough. You may have trouble firing your car up when it is cold. Fuel mileage and acceleration will go down and hydrocarbon emissions will increase. Too many misfires will result in your vehicle failing an emissions test, making it challenging to register or sell. It might even cause enough raw fuel to be dumped into the exhaust to overheat and damage the catalytic converter. Or worse, heat up the temperature enough to melt down the converter substrate which could block up the exhaust system.

What Makes A Spark Plug Go Bad?

A spark plug is fouled when it has become contaminated with fuel or oil. This prevents it from generating a spark. Once the plugs get hot enough, they can burn the contaminates off. This works well if you generally make longer trips. Unfortunately, when you make short, frequent trips, the plugs don’t get hot enough. You’ll have to get them replaced more often.

Properly replacing spark plugs means getting the correct “heat range.” A cold plug has a shorter insulator nose length and is better for high rpm engines. On the other hand, lower rpm engines benefit from a hot plug that cleans the plug when it operates at a slower pace. Each spark plug brand is unique and heat ranges are not universal. This is just one of the reasons why it is helpful to bring your car to a trusted automotive repair professional. We will make sure your spark plugs are at the center of the party. And for all the right reasons!