6 Reasons Car Runs Worse After Changing Spark Plugs

Perhaps, you tried to replace your car’s spark plugs and now wondering why your car runs worse after changing spark plugs. Your car is a complicated machine that depends on a variety of elements to function properly and with a bad spark plug, your car will not function well. One of the most crucial components of a vehicle engine is the spark plug, which serves as an ignition source for combustion. This article discusses the reasons why your car runs worse after changing spark plugs.

Car runs worse after changing spark plugs [how to fix]

To operate at best, your car has to be serviced frequently. The performance of your car may be impacted by how old your spark plugs are. Meanwhile, you shouldn’t panic if you recently changed your spark plugs and now your car runs worse after doing so. There are a few factors that might be the reason why your car runs worse after changing spark plugs. They include the following:

1. Wrong spark plugs type

If your engine won’t always start, your spark plug may be worn out. On the other hand, for your engine to start, a spark plug must ignite a flame and ignite fuel and air explosively.

Installing the incorrect size of spark plugs may result in serious damage, so be careful to do it correctly. Your spark plugs could wear out over time, so you have to replace them before the problem worsens.

How to fix:

To fix this issue, you must ensure you get the right spark plug type needed for your car engine to have optimum performance.

2. Improper gap

For each cylinder to ignite at the exact time, spark plugs depend on having the proper spark gap. A gap that is too wide might cause malfunctions or even damage to the componentry.

How to fix:

While fixing the new spark plugs in your car engine, ensure there is not too much gap so that your car engine will not malfunction. The right space or gap is the correct thing to do.

3. False/wrong torque

Many engines need appropriate torqued spark plugs to function. For the plug to fit into the cylinder head of your engine effectively, torque specifications are essential. Spark plug damaged by over-torqued installation will not work well. This, you should replace it immediately to protect your engine.

Too little torque may lead to a loose spark plug, which might fall out and seriously harm another component of your engine.

How to fix:

To ensure the best engine performance for your car, ensure you use the right size of torque spark plugs. This will ensure your spark plugs work well and your car does not worsen.

4. Broken or damaged spark plug wire

Spark plug wires are a crucial part of the majority of engines. The plug wires are prone to damage, particularly when they are overtightened. Spark plug wires need to be changed since they deteriorate with age and cause performance issues.

How to fix:

If your spark plug wires are damaged, then your car will run worse. To avoid and fix this issue, ensure you get the best new spark plug wire.

5. Just a single spark plug was replaced

Most people think that replacing every spark plug in an engine at once is either too labor-intensive or too costly. Your engine will lack power and use more fuel if all the spark plugs aren’t replaced.

 How to fix:

To fix this, make sure that you replace all spark plugs in your car engine and not just a single faulty spark plug.

6. Miswired spark plug wire

Your car will never operate properly if you have a miswired spark plug wire. If you have ever changed the spark plugs in your car and observed that it won’t start or operate correctly, one of the wires has likely been miswired and the others have reversed polarity.

What are spark plug wires?

You probably already know that spark plug wires are crucial to the ignition system of your car if you own one.  They provide power to the spark plugs from the battery. Each spark plug wire receives electricity via a relay.

Between the spark plug and the ignition coil, spark plug wires transmit a charge. They may be single, double, or triple leads, and the majority of engines employ two of them.

Meanwhile, spark plug wires cannot be switched out. These wires are an essential part of the engine of your car.

The resistance of each wire varies, affecting how hot the spark has to be to ignite the fuel combination. Your car won’t operate effectively if the temperature is either too high or too low for the spark to properly ignite.

How to fix:

Wiring the spark plug wire correctly will prevent your car from running worse after changing spark plugs. Additionally, ensure you follow the proper manual of your car to prevent miswiring the spark plug wire.

What are the effects of wrong spark plugs?

Spark plugs are often one of the more complicated car components. Every car owner should think carefully before replacing it with another one. Additionally, to guarantee greater fuel efficiency, spark plugs enhance engine performance and assist safeguard your engine from different threats.

Here are the consequences of wrong spark plugs replacement:

a. Rough idle

Even though most drivers are aware of the term “idling,” many do not know what it entails. When your car is running but not moving, the process is referred to as idling.

Even while a rough idle may not appear significant, it might indicate that a severe issue is brewing within the engine of your car. As with any issue, the first step is to identify the precise cause. Idling irregularly may sometimes be a symptom of an engine problem or be brought on by issues with the car’s other components. The way your car’s engine idles depends on the sort of vehicle you have. But a few typical reasons are as follows:

• Vacuum leak
• Dirty fuel injector
• Dirty spark plugs
• Bad mass airflow sensor

b. Torque

Spark plugs are turned in with the prescribed torque, which measures rotational force. When you subsequently remove the plugs, they might easily suffer damage or even break off if you don’t tighten them to the proper tension.

The engine’s plugs must be inserted with the correct amount of torque. Be aware that if the torque is too low, vibration or leaking of combustion gas might cause the plugs to come free, thereby harming the engine and the plugs.

The crimping between the insulator and the housing, on the other hand, might become loose if the torque is too great, endangering the integrity of the seal or snapping the mounting screw thread.

c. Engine misfire

When one of your cylinders doesn’t ignite properly, your engine misfires. They cause a small explosion by compressing a fuel and air combination, which moves a piston within your cylinder and propels your wheels.

You may not even notice if just one cylinder is misfiring. However, you will see and feel it as rough idling and diminished performance if numerous cylinders are misfiring. A reduction in fuel efficiency and shaking or rattling from below your hood are some potential symptoms.

What can go wrong changing spark plugs?

Spark plug replacement may be challenging since there are so many things to take into account. Although it may look easy, it’s not. Your engine will suffer considerable harm if improper spark plugs are used. The piston may be struck if the electrode extends beyond a safe distance.

Misfires may occur if it is too short. The incorrect plug could potentially be installed. If the threads are not exactly aligned, the cylinder head’s threads may be damaged, cross-threaded, or seized.

That said, will replacing spark plugs stop a misfire? Your spark plugs may be unclean or worn out if you’re experiencing misfires. There are problems with acceleration, low fuel efficiency, and harsh idling. Additionally, if you accelerate at low speeds, you can feel a loss of horsepower. It’s time to change your spark plugs if you encounter any of these symptoms.

Bad spark plug symptoms

Spark plugs are small, comparatively straightforward devices. It is one of the most crucial aspects of a car engine’s performance since they are used to ignite a fuel-air combination at the proper moment during combustion.

A faulty or bad spark plug might harm the engine and prevent the car from starting or operating correctly. For automotive engines, the symptoms of a damaged spark plug are often obvious. These are a few of the contributing elements to spark plug failure:

• Excessive fuel consumption
• Poor power and acceleration
• Difficulty starting your car
• Engine misfiring

Do you need to tune your car after changing the spark plugs?

Your engine will run more effectively and efficiently after you change the spark plugs. So, a tune-up is necessary if your spark plugs have just been changed. Additionally, this might improve the performance and efficiency of your car.

Is a torque wrench required for spark plugs?

The answer – It is not necessary. However, a torque wrench may be used to guarantee that your spark plugs are correctly tightened. Avoid over-tightening to avoid breaking the block’s threads and under-tightening to avoid preventing plugs from firing. Use caution while tightening spark plugs with a torque wrench since they are prone to breaking within the hole.

Can new spark plugs cause rough idle?

A new spark plug wire often has the potential to shorten the ignition coil or its wires. The car won’t start or function properly if this happens. Check the coil resistance or voltage as directed in your owner’s manual to identify a rough idle issue brought on by a new spark plug wire.

Will old spark plugs result in a rough idle?

An old set of spark plugs may be the cause of your rough idle. A rough idle is one problem that often arises from outdated spark plugs. When you initially start the car, if you hear a loud exhaust rattle and a rough idle, your spark plugs may have burned out and caused your current issues.

As mentioned earlier, spark plugs are important for a car to function efficiently. There is every possibility your car runs worse after changing spark plugs and this is due to some factors outlined in this article. If you know how to replace spark plugs, you may save hundreds of dollars while using your car.