Home / Engine / 6 Warning Signs of Bad Spark Plugs & Replacement Cost

6 Warning Signs of Bad Spark Plugs & Replacement Cost


Car startup problems are not something new to car owners. Chances are, you have encountered a situation where your car could not start up. Any mechanic would tell you if your car is experiencing problems when starting up, it could very well be due to worn out spark plugs or the ignition wires.

But, how can you tell the signs of bad spark plugs? It turns out this is not rocket science and any person with a basic understanding of automobiles can comprehend any problems arising from the spark plug. Before we navigate the telltale signs of a worn-out spark plug, what are they?

So, What Are Spark Plugs?

Spark plugs You may have heard of the spark plugs or maybe read about it in your car manual, but probably you don’t understand what it is. Or better yet, you have seen the component, but you don’t have a clue what it’s called. Well, spark plugs are the integrated system for ignition. They are what I would call, the core of the ignition component system.

What is the role of Spark Plugs?

The system receives electric current in high voltage and ignites the fuel/air combination in the combustion. The electric voltage is received from the ignition coils and helps to sustain your car in motion. As long as the pistons of your car engine are in motion, the car continues to rev up while at the same time producing smoother and combined mixture of fuel/air.

What are some of the signs of faulty spark plugs?

Without a spark, we would not have cars moving since no fuel would go through combustion. Most automobile companies advise car owners to replace their spark plugs after every 30000 up to 50000 miles. It is imperative to understand some of the signs of failing or worn out so you to consider replacing spark plugs with a certified mechanic.

5 Common Signs of a Failed Spark Plug

Most sparks sometimes causes an airfuel mixture in the combustion chamber. Without regular car maintenance done, most likely your plug wires will eventually fail. Read the following list:

High Consumption of Fuel

Spark plugs that function properly ensure minimal emission from your car. This is contrary to worn our spark plugs which increase emission hence reducing your car’s fuel economy because of the incomplete combustion process. Additionally, worn spark plugs have electrodes that are closed up or expanded. This has a bearing on your cars fuel efficiency.

Problems during Ignition

The spark plugs are the core of the ignition component system that can cause ignition problems especially when they are worn out. Without sparks, the car won’t move since there would not be any combustion process. Spark plugs are usually overlooked especially when your car has ignition problems. This is because they are not top of the mind components we think about whenever we are searching for the problems in starting up a car.

Rough Idling of the Engine

Whenever your car is in a state of no motion and your engine idles, a spluttering sound with increasing vibrations are often viewed a sign of a faulty spark plug.

A Drop in Car Fuel Mileage

Another common sign of a worn out spark plug is low mileage. If the fuel you use is consistent but you still experience low mileage, it could be a symptoms of bad spark plugs. A reduced mileage can be a sign of a blocked fuel filter or even a broken spark plug. It is imperative to use the right plugs for your car as recommended by the manufacturer for optimal performance and mileage.

Poor Acceleration

When your car has poor acceleration, it could be a hint to have your spark plugs checked and replaced. Poor acceleration may include delayed reaction or even lack of response when revving your gas pedal. I such a scenario, pushing the gas pedal down do not cause any immediate boost in the speed of the car. This may cause the engine to appear being overworked therefore lots of fuel consumption. The lack of acceleration can reduce your gas mileage performance.

Engine Misfires

Worn out spark plugs can also cause engine misfires. However, modern cars can have the same problem due to a sensor malfunction. In the case of worn out spark plugs, the problem could result when the wire of the spark plug has been damaged. An Engine misfire results to intermittent sputtering or stumbling sound. Also, check the fuel pressure regulator if you find it hard starting your vehicle.

How long should you wait before replacing your Spark Plugs?

According to most auto manufacturers, you should replace the spark plugs once your car has a mileage of 30000 to 50000. Additionally, other factors such as the type of the spark plug and the condition of the car do impact the longevity of your car’s spark plugs. They are made of copper have a short life compared to other common types of spark plugs made using durable material.

How can you test a worn out spark plug?

  • Firstly, remove the spark plug and valve covers
  • Keep the spark plug in the spark plug cable
  • Place the plugs on the frame
  • Ignite the car and observe for any sparks
  • You can also get changed spark plugs or checked by a certified mechanic

What should you expect when you replace your car plugs?

Changing your car’s plugs after they’re worn out comes with numerous benefits. A new Spark Plug ensures your car Ignites without any hesitation giving you the confidence to enjoy your ride. New Spark Plugs:

Improve the Fuel efficiency

According to data from National Institute for Automotive Service Excellence, misfiring sparks reduces efficiency of fuel by about 30%. When new spark plugs are replaced, fuel efficiency is maximized thereby saving on cost.

Reduce emission by your car

The Environmental Protection Agency reported that regular turn ups of engine save gas while at the same time reducing harmful gas emission.

Easy start of your car

Igniting your car with new Iridium Spark Plugs often feels like revving a new engine. If the installation is successful, performance and ignition problems will be a history.

Check out this You Tube video that will give you a more comprehensive and easy to understand concepts on how to replace your car’s plugs when they’re worn out.

Final Troubleshoot Advice

Most experienced mechanics are usually very good at troubleshooting a bad spark plug symptoms. A typical symptom occurs when you hear an engine crank without successfully starting. Also, other common symptoms are a check engine light on, car shakes, faulty ignition system, blown cylinder heads or engine electrical misfire. Sometimes you can get lucky and it is just that you need your battery changed.

Preventative maintenance and constant car maintenance can help reduce the chances of your plugs failure. Changing the plugs yourself can help you save the spark plugs replacement cost, and improve any bad fuel performance or any poor fuel economy.

Sometimes it is hard to start or you might experience trouble starting your vehicle in cold weather. I would love to hear from you so feel free to comment or ask any questions on bad spark plugs sign. Don’t forget to get a maintenance schedule with a local mechanic instead of replacing the spark plugs yourself.

Last Updated on: July 13, 2022

This div height required for enabling the sticky sidebar