Updated at: 19-05-2022 - By: Lucas

Almost everyone who owns a car has had problems with the engine at some point. The problem is sometimes with the way the engine starts. It means that either your battery is weak or your spark plugs are worn out. Here’s how to make sure.

Bad spark plugs symptoms

If your engine light is blinking and your engine isn’t running as smoothly as it should, you should check your spark plugs. The engine needs spark plugs to work well. If they don’t work, your car will have problems that can hurt the engine.

Before we start looking for signs, we need to know what spark plugs do in the ignition system.

Without a spark plug, your car will never start. The spark plug sends out an electric spark that starts and keeps your engine running.

Common signs of a faulty Spark Plug

bad spark plugs symptoms

These signs will let you know if your spark plug is bad or not.

When your engine misfires

When this happens, the check engine light will always flash. This means the fuel isn’t burning all the way, which can cause the following.

Problems with the engine knocking and other major mechanical issues

Loss of power and trouble with performance

Carbon will build up on the spark plug.

Intermittent strange engine sounds

Poor fuel economy

This is a pretty common sign. Your fuel use will go up by a lot. A car with bad spark plugs can use up to 30 percent more gas.

You should also think about how much carbon your car gives off. If your engine is making black smoke, it means that something is wrong with it. If the gap has grown, you should check your spark plugs and gauge.

When spark plugs are worn out, they don’t work right and send junk into the combustion chamber. It then gets dirt and dust on the parts that move.

Your engine backfires

It means that the ratio of fuel to air in your car isn’t right. So, fuel particles that haven’t been burned will explode in the exhaust system. This needs to be fixed right away because it could hurt the catalytic converter.

Engine knock

This is a serious case that, if not fixed, could cause a lot of damage to the machine. You could hurt the following parts of the engine.

Head of piston. After an engine knock, the piston head doesn’t take long to follow. If the knock is very strong, it could make a hole in the piston’s head.

Compression rings for pistons. Even though this isn’t as bad as losing a piston head, the engine will still need a full repair.

If the pressure in the combustion chamber stays high for a long time, the cylinder head could get holes in it.

Cylinder head valves could melt

All of these knocks could cause metal particles to get into the lubrication system, which could cause other engine parts to break.

Your vehicle will lose acceleration power

Not many other things affect the speed. You could lose up to 40% of your power to speed up. When your car’s acceleration power goes down, you tend to use more gas.

Rough idle and hard start

When your engine is just sitting there, it sounds rough and jittery. Also, it will make your car shake. This means that when your car is at idle, one of the cylinders doesn’t fire right.

When your car takes longer to start, this is called a “hard start.” It usually means that the spark plug isn’t getting enough spark to start the engine. If the problem keeps happening, the ignition will have trouble if the car is hard to start.

What are the costs of replacing your spark plugs?

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The price depends on what kind of car you have. Some of them have more than others. You can count the cylinders to figure out how many spark plugs your car has. But some cars have two sets of spark plugs. A V4 engine, which has four cylinders, is one example. There are two spark plugs in each cylinder.

No matter how many cylinders your car has, it’s usually cheap to change the spark plugs. Less than $10 can be spent on a single spark plug. Having a mechanic change all of the plugs and do the work should cost between $40 and $150. It’s not a hard process, so it shouldn’t take the mechanic more than an hour.

When Do I Replace My Spark plugs

Spark plugs can last for a long time before they need to be changed. But car manufacturers say that you should change them every 30,000 miles.

The type of spark plug determines how long it will last. Platinum or iridium spark plugs last much longer than copper ones.

Always use the spark plugs that came with the car when you need to replace them. If you can’t find the same spark plug, you should replace it with a good one. Copper plugs aren’t very good, and they’ll wear out quickly.

How to Replace Your Spark Plugs

The process depends on what kind of car you have. Some models are easy to switch out, but others require more skill. Some V-engine cars have spark plugs that are hard to get to. You might end up opening different engine parts. But no matter what kind of car you have, the way to change the spark plug is the same.

It consists of

To take out all of the keys and coins

Taking off any parts that are on top of the ignition coils or cables

Take out any spark plugs that are broken and replace them with good ones.

Check the lengths of the sparks to make sure you have the right ones. Pistons can be hurt by spark plugs that are too long.

Use lube to grease the threads and a torque to tighten them.

Bring back everything you took off, including the cables and coils that start the engine.

Spark plugs come in different kinds. Some are thought to be better than others. No spark plug on the market is bad. The difference is that some make bigger sparks than others. Iridium and platinum spark plugs are better than standard ones.

Spark plugs made by Bosch that are platinum plus. They last 25% longer than the last version of Bosch platinum spark plugs and are more durable. Both plugs increase the MPG.

Iridium spark plugs made by Bosch. This is a high-performance plug from the next generation. They light faster than copper plugs and last four times longer. throttle and acceleration power that works well.

Tips for maintaining your spark plugs

Here, you might want to think about preventive maintenance. Closely watch your car to see if anything changes. Keep an eye out for the warning signs. This is not where it ends. Use these simple steps to get a better diagnosis.

Inspect wires

Find a place under the hood of your car that has enough light and is open. Find the wires for the spark plugs and look at them. Check the cables for damage. Cuts and scorch marks. Look for signs of rusting.

Run your engine

Listen for sounds that could be caused by electricity. Listen to how your engine sounds. A high voltage leak could be the cause of a noise.

Use water to spray the wires

Spray the parts of the boots where they connect to the spark plugs. If the engine is arcing or there is mist, turn it off. Take the spark plug out of the trunk and look for signs of carbon tracking inside the trunk. If there is carbon tracking, the spark plug will need to be replaced.

Use a spark plug tester

A spark miss or spark misfire can cause your engine to lose power and give off black smoke. Use this check list to figure out if your plug is misfiring.

Take the spark plug out of the spark plug lead.

Connect your spark plug tester to the plug’s lead.

Connect the spark plug to the tester and make a link between the plug and the lead.

Start your engine up again and listen for a gap in the timing.

Confirm if the wires to your spark plug are routed well.

Cross-cutting uses up a lot of your car’s power. Use the manual for your car to figure out which wire goes to which port.

Clean your spark plugs.

Separate the spark plug from the lead that goes to it. Make sure to clean the spark plug well so that nothing gets into the combustion chamber. Do not use force or your hands to take out the spark plug. Use the socket wrench for spark plugs.

To get rid of any deposits, use a spray and a wire brush. Never clean your spark plugs with something rough.


Spark plugs are a key part of making sure your engine is in good shape. To keep the engine from knocking, they should be changed at regular intervals. Spark plugs are also inexpensive. Change all of the spark plugs, not just the one that is worn out.

Spark plugs have to wear out at some point. So, you should be proactive about taking care of your engine. Check for signs that the spark plugs are worn out. This kind of check-up will save you money and keep your engine in good shape.

Most engine failures caused by spark plugs will probably not happen if you take care of your car regularly. When it’s time for service, you should stick to the performance service dates and not add more miles. Tell your mechanic how your car feels. This will help them fix it.

In the end, our cars show how well we take care of them. As with everything else. If you don’t deal with problems before they start, you’re setting yourself up for bigger ones. Preventive maintenance is the first step toward safety and a good-running engine.