Misfire on 2 Cylinders – What Are The Underlying Reasons?

Misfire on 2 cylinders (more commonly known as engine misfires) is no stranger to drivers, even seasoned ones.

There’s a sudden lack of power in your engines, causing sluggish starters and lackluster performances. You can imagine all the disasters that might follow if you persistently ignore the dilemma!

Still, going blindly into it is a huge No; if you try to fix the problem without understanding the symptoms and functions, things will only worsen.

That’s why this article is crafted to give you more insights into the matter. Click for more info.

What Causes A Misfire On 2 Cylinders? The Common Symptoms

Misfire on 2 Cylinders

The most common reasons are: ignition system issues, fuel delivery problems (ex: damaged injector circuits or faulty fuel injectors), and engine mechanical errors (ex: weak piston ring or sticking valves).

But numerous factors are at play regarding a cylinder misfire (or P0302 misfire codes).

You should also note that if other trouble codes go with P0202, chances are there is more than just one culprit. The code P0202 itself indicates problems with Cylinder 2.

Meanwhile, multiple misfiring engine codes imply more serious issues – such as low fuel pressures or vacuum leaks – which may affect different cylinders inside the car.

Nevertheless, we must admit that diagnosing and differentiating the codes might be challenging; consistent cylinder misfires usually push the PCM/ECM to shut its injectors entirely to protect catalytic converters.

To make matters worse, the PCM sometimes gets confused and causes tons of misfiring codes (including P0300) to set off simultaneously.

That’s why keeping an eye on more intricate symptoms of P0302 is important. A vehicle with misfiring engine issues is expected to exhibit the following signals:

  • Too much fuel consumption
  • Incomplete combustion
  • Notable power decrease
  • Foul exhaust odor
  • Troubles starting the car engine
  • Stalling
  • Running rough
  • Flashing or blinking check engine lights

What Is The Consequence Of Misfire On 2 Cylinders?

When cylinder misfires happen, the car engine will momentarily stumble and lose its speed (RPMs). Even though that might dissipate and send your car back to its normal condition, do not yet rejoice.

No immediate treatments or fixes mean such misfires will likely happen again soon, shortening your car’s lifespan as a result.

Worse, a cylinder two misfire equates to taxing the car engine. Numerous misfiring incidents that occur back to back can strain the engine components, leading to more severe issues later on.

Cases in point include valve opening burning, back pressure via the intake, and high head pressure.

The car engine is not designed for those tasks, so it’s not a surprise that it only worsens and worsens every time you bring the vehicle onto the road.

How To Fix A Cylinder 2 Misfire

How to Fix A Cylinder 2 Misfire

How do you fix a cylinder 2 misfire/ 2 cylinders misfiring? Choose one of the two methods for cylinder 2 misfire repair illustrated below.

Method 1. Fix The Fuel and Air Misfires

Step 1. Narrow the cause via other error codes.

When using diagnostic scanners to inspect whether there is any specific cylinder error code, you might realize other codes also pop up.

Though they are not directly relevant to your current automobile misfire, do not jump to the conclusion; surprises might await! 

For instance, if there are error codes regarding fuel deliveries (pumps, injectors), O2 sensors, or mass airflow sensors (check quick tips for resetting here), they might be indirect culprits that led to the misfire.

Other scenarios to consider:

  • If the car misfire does not point to any specific cylinder, chances are your engine does not get sufficient fuel or air for proper operation, which stems from failing fuel systems.
  • When the oxygen or airflow sensors fail, they might provide your engine computer with incorrect data, causing misfires.

Step 2. Identify and seal vacuum leaks

Broken vacuum lines might push your fuel injected motor to misfire; so you should look around the bay for damaged or severed rubber lines from the intake manifold (often located near the engine’s top with a linked intake).

After that, replace any malfunctioning vacuum line you can find. That can resolve the car misfire – or at least make your engine run much better.

Step 3. Disconnect every fuel injector one by one and look for changes.

Suppose you still struggle to find the misfiring cylinders; it’s time to disconnect the fuel injector’s power to inspect how it might affect the engine.

Find the connector’s connection to the injector’s back. (you may consult a repair manual when encountering any difficulty). Then observe what’s happening next: 

  • If the car runs worse after disconnecting one injector, reconnect it before moving on to other ones. 
  • If the engine behaviors experience no changes, the cylinder is obviously not firing, which is the root of all your problems.

Step 4. Test the fuel system

Attach the fuel pump and pressure gauge located near the engine’s fuel rail end.

Look up the right pressure specifications in the vehicle’s repair manual and compare them to your readings of the idle engine. After that, go on to put them against the RPMs mentioned in the manual.

Is the pressure inconsistent or low? Then it’s clear the fuel systems before the rail have caused the misfire. In this case, you must replace the fuel pumps or filters.

That involves removing the pump from the tank – which might be a bit too much for some inexperienced drivers. Seeking help from professional mechanics will be your best bet.

Step 5. Replace your fuel injectors if they are not working

Link the battery’s negative terminal to some test lights. Next, press the probes into the wires that lead to each injector.

Does the light come on? It means energy is flowing into every injector. Otherwise, there are possible electrical issues that demand professional services and inspections.

If the scanner announces error codes specifically related to the injectors, then the issue is much simpler: you only need to replace that injector.

Sometimes, cleaning it is enough: pour some system cleaner into the gas tank, and you are all set!

Step 6. Replace your oxygen or mass airflow sensors if they suffer from errors

Should the scanner imply that your oxygen/airflow sensors undergo problems, they might be the root cause behind the misfire.

A standard airflow sensor is often installed right on the automobile intake pipe, past the filters. Meanwhile, oxygen sensors usually stay on the exhaust, right in front of the catalytic converters.

Remove the airflow sensors by extracting the screws that bind them to the intake. Then disconnect the wiring pigtails that lead into the devices.

And in the case of oxygen sensors, disconnect and unscrew the wires using oxygen sensor sockets.

Method 2. Address Mechanical or Electrical Misfires

Step 1. Check the spark plugs in your vehicle for damage signs.

Once you have already figured out which cylinders are misfiring, the first step is to disconnect all the plug wires going into their spark plugs – preferably using spark plug sockets.

The damage will help determine where the misfire cause comes from.

If the operational issue is merely because the plug is old, replacing it is enough to resolve your current problem. Ensure the new spark plug is properly gapped and positioned.

Step 2. Test the ignition coil pack using a multimeter.

A spark plug ignites the fuel and air mixture via transmitted currents from the car’s coil pack, which means random misfires will ensue if this compartment is faulty.

Most modern vehicles offer specific fault codes for coils going bad. Nevertheless, it’s easy to test that by yourself: simply disconnect the plug wire and connect Ohmmeters to its two pins.

And do not forget to perform a quick compression test, which confirms whether the inline spark, fuel, and air are in order.

Step 3. Remove the head gaskets if there’s no compression in the nearby cylinders.

Misfires in 2 cylinders close to each other imply blown head gaskets, which is shown in the oil coolant, bluish exhaust smokes, and oil leaks. Remove these gaskets and install new ones in their places.


Our inclusive and well-researched articles have dived deep into all underlying issues and appropriate fixes regarding misfire on 2 cylinders.

Though the steps to troubleshoot the problem are not difficult, they DO require a certain level of attention and caution.

Follow our guidelines carefully, and do not skip any seemingly small detail. Grasping the full-fledged consequences of engine misfires is also critical.

As always, you are welcome to write to us with more questions or clarifications about the first and second cylinder misfire.

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