Cylinder 2 Misfire After Spark Plug Change: Causes and Fixes

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Cylinder 2 misfire after spark plug change can be a scary discovery. A clogged gas injector is a common reason your cylinder can misfire after spark plug change.

Cylinder 2 Misfire

This article explains other leading causes of this problem and how to fix it.

Why Is There a Cylinder 2 Misfire After a Spark Plug Change?

There is a cylinder 2 misfire after a spark plug change because of a clogged fuel injector or an insufficient air intake. Also, other issues such as low compression, sensor problems, or a faulty piston can cause your cylinder 2 to misfire after a spark plug change.

  • Blocked Gas Injector

A blocked gas injector can be one of the reasons why cylinder 2 misfires after a change of spark plugs. When a gas injector is clogged, it impedes the proper delivery of fuel into the combustion chamber. This results in an inadequate fuel-air mixture, leading to your car misfiring.

Also, a blocked gas injector may not spray the correct amount of gas into the chamber. As a result, the gas may be insufficient, and the spark plug may struggle to ignite the mixture, causing a misfire in cylinder 2.

  • Insufficient Compression

Another reason for an engine misfire even after changing the ignition plug is that the compression is low. Compression refers to the pressure created inside the combustion chamber as a result of the piston moving upward. This upward movement compresses the air-fuel mixture to generate strong combustion. However, the air-fuel mixture may not ignite effectively if the compression is insufficient, and this will lead to a cylinder misfire.

  • Sensor Issues

Sensor issues, especially the ones affiliated with the ignition chamber, can cause cylinder 2 to misfire after change of spark plugs. A malfunctioning sensor can halt the ignition system’s synchronization and timing, leading to a consistently weak spark.


For example, the crankshaft position sensor (CPS) monitors the crankshaft’s position and speed. A faulty CPS will send incorrect signals to the ECU, leading to a misfire. Also, the ignition control module, which controls the speed and duration of the induction coil, can wear out. This can cause timing issues of the spark in cylinder 2, causing misfires.

  • Poor Air Intake

Poor air intake is another culprit that causes your cylinder 2 to misfire after you change the spark plugs. The air intake is responsible for delivering a good air-fuel mixture to the combustion chamber.

Car Misfiring Problem

When the engine takes in air, it passes through the air filter and intake manifold before it reaches the combustion chamber. If the air intake system is compromised, it can disrupt this balance, leading to a misfire.

Poor air intake means reduced oxygen left for combustion. This results in a lean fuel-air mixture and can cause cylinder 2 to experience a misfire since the spark plug may struggle to ignite the insufficient mixture. Also, a leak in the air intake can introduce unfiltered air, which disrupts the air-fuel mixture ratio. This can either lead to a lean or rich mixture. In the case of a lean mixture, cylinder 2 may misfire.

  • Worn-out Ignition Coils

A worn-out induction coil can be a significant factor in the misfiring of your cylinder 2. The induction coil generates the voltage necessary to create a spark at the spark plugs. If the induction coil is worn-out, it may not be able to create the required power necessary for a spark.

As the induction coil deteriorates over time, it may lose its ability to generate the necessary spark. This reduced spark may cause incomplete combustion, leading to misfiring. A worn-out induction coil can also lead to wear of its components, like the primary and secondary windings. This wear can lead to electrical faults, which can disrupt voltage flow and timing and lead to misfires.

In some cases, it can even generate excessive electricity between its components. This can cause misfiring between adjacent cylinders, including cylinder 2.

  • Damaged Piston

A damaged piston can be another reason your cylinder 2 misfires even after changing spark plugs. The piston plays a vital role by helping to compress the air-fuel mixture and transmit the force to the crankshaft. If it is damaged, it can lead to a loss of compression in cylinder 2. Insufficient compression results in an incomplete combustion process, leading to a misfire.

Also, if the piston is broken, it may allow copious amounts of oil to enter the combustion chamber. This can affect the air-fuel ratio and cause irregular combustion. These irregular combustions can then lead to a misfire in cylinder 2.

Due to excessive wear and tear, improper piston clearance, or a damaged piston, there can be a case of a piston slap. This can result in an uneven combustion process, causing the cylinder to misfire.

How To Fix Cylinder 2 Misfire After a Spark Plug Change

To fix your cylinder 2 misfiring after a spark plug change, you can clean the fuel injector, use an air intake cleaner, or replace the blown gasket. You can also replace the piston and sensors or fix your car’s compression.

  • Clean the Gas Injector

Cleaning the gas injector can help fix cylinder 2 misfire after an ignition plug change. Cleaning the injector will remove any deposits, such as carbon sediments or dirt. These deposits obstruct the nozzles in the injector, resulting in improper fuel patterns.

Cleaning the injector will remove the obstructions and restore the cylinder to its proper functionality. Cleaning the gas injector also helps address the atomization process, whereby gas is broken down into small bits. A clean injector leads to a better atomization process, which allows for more combustion and minimizes the potential for misfires.

  • Use Air Intake Purifier

Using an air intake cleaner can help prevent cylinder 2 from misfiring by improving the air-fuel mixture that enters the combustion chamber. While gas injectors majorly regulate gas delivery, the air intake system ensures proper airflow. By using a cleaner, you can effectively remove the deposits, such as dirt or oil residue, that build up in the air intake system. This allows for better airflow and a lower likelihood of misfires.

Fix Misfiring Cylinder

Additionally, cleaning the air intake system can enhance the performance of sensors like oxygen sensors or mass airflow sensors. These sensors help to measure and regulate the air-fuel mixture. Once they become contaminated due to dirty air intake, they start to provide inaccurate readings, leading to misfiring. You can prevent this and maintain the accuracy of these sensors by ensuring proper feedback to the engine control unit and promoting better fuel delivery and ignition timing.

  • Fix the Compression

You can stop your cylinders from misfiring by fixing the air compression. Cylinders often misfire when there’s insufficient pressure to ignite the air-fuel mixture. The first step to fixing your compression issue is to do a compression gauge to test if your engine has low compression.

If you don’t have a compression gauge, you can either buy one or take your car to the nearest auto mechanic to test it for you. If it is confirmed that your compression is low, the next thing is to inspect the valves and gasket to see if any of them are broken.

  • Replace Your Sensors

You can fix your misfiring cylinders by replacing your mass air flow or oxygen sensors. The mass air flow sensor is located on the intake pipe, while the oxygen sensors are located on your vehicle’s exhaust, right before the catalytic converter.

To replace the MAF sensor, remove the two screws that hold it in place and disconnect the wiring connections from it. You can also do the same with the O2 sensor by disconnecting and unscrewing the connections. Make sure you connect the new sensors with the same wires you disconnected from the old ones and secure them using the mounting hardware.

  • Replace the Coil Pack

You can solve the misfiring problem by replacing the ignition coil pack. While many vehicles provide a specific signal when this goes bad, you can confirm if the coil needs to be replaced by connecting an ohmmeter to the pins. Compare the resistance you get via the ohmmeter to the resistance specifications of your vehicle. If they do not match, you need to replace your coil pack.

You can replace the coil by disconnecting it from the other wiring connections and unbolting it from the bracket. Insert the new coil and reconnect it like the old one. Depending on the severity, replacing spark plugs might be another component you need to fix.

  • Replace Blown Gasket

If you are experiencing a misfire between two cylinders, a blown gasket is a likely culprit. In this case, you might need to replace your gasket. Other signs of a blown gasket include finding a bright green fluid in your oil, a bluish smoke exhaust, and an oil spill between the top half of the cylinder head and the engine’s bottom end.

Unfortunately, you can not replace a blown gasket by yourself as it is a pretty complicated process that requires many specialized tools. If your gasket needs to be replaced, take it to a certified auto mechanic.

  • Install a New Piston

You can fix a misfiring cylinder by replacing the piston. To do this, you might need to remove all the necessary components, including the cylinder head. Disconnect the connecting rod from the crankshaft and dislodge the piston from the cylinder bore. Examine each component and clean it thoroughly.

It is at this point that you install the new piston. Lubricate each piston ring and insert each new piston into the cylinder bore. Attach the connecting rod to the cylinder bore using new screws. Start the engine and check for any weird sounds or sputtering, then perform a test drive to confirm that the misfire is resolved.


– Should You Do Anything After Changing Spark Plugs?

Yes, you should do something after changing the spark plugs. Start your engine to ensure the plugs are working as they should. If the engine revs up without any issues, you fixed the plugs correctly. If, on the other hand, it doesn’t start, you might need to consult your mechanic.

– How Often Should You Replace Your Spark Plugs?

You should replace your spark plugs every 30,000-50,000 miles if your car uses copper or nickel spark plugs. If it’s a platinum or iridium ignition plug, you need to change it every 60,000-150,000 miles. The frequency depends on the type of spark plug your car uses.


What Could be Causing a Cylinder 2 Misfire After Changing the Spark Plug?

After changing the spark plug, a cylinder 2 misfire might be caused by carbon fouled spark plugs. This build-up of carbon on the spark plug can prevent proper ignition, leading to a misfire. Regular maintenance, such as cleaning or replacing carbon fouled spark plugs, can help prevent this issue and improve engine performance.


Having read this article, you don’t need to be anxious if your engine misfires after an ignition plug change.

Below is a summary of the main points discussed in the article:

  • Your cylinder 2 misfires after a spark plug change due to a clogged diesel injector or a bad air intake.
  • Other reasons are low compression, sensor issues, worn-out induction coil, or a faulty piston.
  • You can fix misfiring cylinders by cleaning the diesel injector or using an air intake cleaner.
  • You can also replace the piston, change a blown gasket, replace the coil pack, or fix your car’s compression.

With the information in this article, once you notice that your cylinder is misfiring, you should be able to diagnose and fix the problem immediately.

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