What happens if you don’t change your spark plugs?

It’s amazing how the smallest of things in life tend to have the most important functions/uses. Older train cars for example are coupled with the link-and pin method which really is such an easy concept with immense magnitude. Similarly, when it comes to cars, spark plugs are very important respective of their size.

So what happens if you don’t change your spark plugs? Simply put, once the spark plugs give up,your car won’t be taking you anywhere.

Read on to understand better why these small parts are important for your cars’ well-being.

What do spark plugs do?

Spark plugs are responsible for providing the spark that is needed to ignite the air and fuel mixture found within the cylinders. In simpler terms, these devices set off a process known as combustion which then ignites the car’s engine, setting your car in motion.

So basically when you turn on the ignition, spark plugs are the ones behind the car starting.

Seeing now how important spark plugs are to your engine, keeping their health at a maximum is priority. Aged or bad sparks will often lead to problems such as misfires, high fuel consumption and pretty much every wrong thing you wouldn’t want happening to your car. Make sure you replace them when necessary to make sure your car continues torun smoothly.

Why should you replace spark plugs?

As we’ve mentioned above, failing to replace your spark plugs will only generate your problems and seeing as they are an easy fix, why not just do it?

These small and mighty devices will eventually age as they are working quite a lot in using electricity to give bursts of energy otherwise referred to as spark, to ignite your engine. Here are some things that could happen to your spark plugs:

Build Up

When the air and fuel mixture are ignited, debris and at times oil do enter the combustion chamber causing deposits to build up on the spark plugs. This is what leads to pre-ignition of the fuel. When this happens, it often results in a jerky car as an unreliable amount of energy is being supplied to your car. All this debris widens the gap and when it’s too far apart, then combustion will be highly ineffective.


The cooling system in your car can have an effect on your spark plugs. If it isn’t working as it should be, then your engine is most likely to run really hot hence overheating the spark plugs and essentially rendering them ineffective. Such extreme temperatures take a toll on these small parts leading them to expand therefore widening the gap.

Wear and Tear

The wear and tear in these sparks comes with age and how often they are in use. So, the more miles covered, the more wear and tear will be on your sparks. The lifespan of most sparks normally is between 10,000 and 20,000 miles but that is changing as some sparks being sold now can last well beyond 60,000 miles.

The material being used in their manufacture has a lot to do in determining their lifespan. Copper for example, is known to have the smallest lifespan whereas other materials such as aluminum have a longer life span. Depending on your car, make sure you find out what spark plugs you’d need to use.

Symptoms that you need to have your spark plugs replaced

  1. Hard time starting your car?

In most cases when cars don’t start, we are often quick to assume that either the battery is dead or we have run out of fuel. What we never seem to consider is what condition our spark plugs are in. While worn out sparks may drain your battery, sparks that have lived out their lifespan are to blame.

The engine is comprised of different parts that work together to ensure your car is running smoothly. When the spark plug is not able to produce the bursts of energy needed to set the car in motion, then nothing will happen until a replacement is made.

Consider having both your battery and spark plugs checked and replaced where necessary.

  1. Rough idle

When a car is stationary, the engine is said to idle and at this position, it gives approximately 1,000rpm (revolutions per mile). The sound you want to hear coming from your engine is smooth and constant. If you however feel as if you’re experiencing an earthquake in your car, then it’s time you drove right to your mechanic to have a look at those sparks before they give in completely. These vibrations are caused by the cylinder misfiring.

  1. Engine surging

The engine surge is caused when during the combustion process, more air than usual is sucked in causing sudden surges in power and then the vehicle slows down. Due to the delay in delivery of power, the car becomes jerky or will continuously start and stop. This behavior could be an indication of a problem with the spark plugs and should be addressed as soon as possible as having this happen on the highways could be detrimental.

  1. Engine misfires

Engine misfires in modern cars are due to sensor malfunctions and not the sparks and are mostly brought on by a problem in the ignition system. When the engine misfires, the car stops for less than a second before proceeding with normal movement. This is probably the case in spark plug issue because, the spark wire or tip of the spark plug that basically connects or joins with the wire is spoilt.

In the case of misfires, you’ll hear a lot of pinging, knocking or rattling coming from your engine which is an indicator that one or more cylinders are misfiring.

Other downsides thatan engine misfire brings are the high emissions it releases into mother earth, decrease in engine power and a poor fuel economy.

  1. Poor acceleration

When your car is having an acceleration problem, it won’t go unnoticed. Despite your efforts at achieving that top speed you like, the response from the engine will be anything but. It almost feels like the car is having a slow day and won’t respond to much. It becomes sluggish.

The solution to the engine’s trouble basically lies in the spark plugs. With every wear and tear inflicted on the poor sparks, the less effective it becomes. How effective the spark plug is will determine your optimum acceleration.

When it comes to acceleration, don’t expect that the problem will only be the spark plug and that’s it. Be open minded and contact your mechanic to look at the filters, injectors or even the sensors.

  1. High fuel consumption

As we’ve seen with the engine misfires, they often result in high fuel consumption as a result of incomplete combustion. This is the case because your engine isn’t getting the appropriate powerheat to generate the spark, at the right time. The decrease can be up to 30% according to The National Institute for Automotive Service Excellence. They say that owning a car is only half the job as sustaining it in terms of fuel it another expense altogether.

Spark plugs are a determining factor on how well or horrible your car will do when it comes to fuel economy. When they’re working at their prime level, the car will get the best fuel economy and this happens when the gap on the spark plug is neither too short nor too far apart.

Benefits to replacing the spark plug

Better fuel economy – By getting some new spark plugs for your car, they maximize the fuel economy saving you a lot of money.

Less harmful emissions – Regular tune-ups for your engine will save you gas and reduce the amount of toxic emissions going into our atmosphere. These tune-ups especially when it comes to the spark plugs reported that difference according to The United States Environmental Protection Agency.

No more misfires – Getting a replacement on your spark plug will be a beautiful experience. Enjoying the smooth driving will make you forget about all your earthquake shenanigans.

Optimal combustion – The combustion system that often suffers when the spark plugs are nearing their expiry date, is rejuvenated creating the best working conditions for the system. If this system is working perfectly, then there are no limitations as to how quickly your car will transition from gear to gear.

Generally, the benefits that replacing your spark plugs will have significant impacts on your car. If you’re probably wondering how you’ll get to checking if they are in good condition, don’t stress yourself. The Family Handymanhas a step by step guide to show you how you can easily change them yourself.

If your car has a more complex engine like a V6, then it’s advised you get a pro if you’re not comfortable with taking apart things like the intake manifold. If that just went over your head, then you should definitely be getting a professional.

So if you have always wondered what happens when you don’t change your spark plugs, now you know and hopefully you’ll take the matter a bit more seriously now. Your safety lies in the whole functionality of the car. Every part has an effect on your safety.

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