Engine Misfire Symptoms: What Is It & How To Fix
This post may contain affiliate links. That means if you click and buy, we may receive a small commission (at zero cost to you). Please see our full disclosure policy for details.
One thing about cars is that they can run smoothly for as long as you want, but they can also surprise us with an issue when we least expect it. One of the common issues associated with a car is a misfire.
An Engine Misfire is when your fuel, oxygen, and spark aren’t functioning properly together. It happens on the cylinders because there is some sort of malfunction. Engine misfiring can be frustrating for the driver and can be caused by several reasons, ranging from wearing pistons to spark plugs.
An Engine Misfire is when your fuel, oxygen, and spark aren’t functioning correctly together. It happens on the cylinders because there is some sort of malfunction. Engine misfiring can be frustrating for the driver and can be caused by several reasons, ranging from wearing pistons to spark plugs.
So what is a misfire? How do we intend to fix this issue without it escalating into something more damaging? What are the things for you to watch out for to know that this is a misfire?
These and many more are the issues this post seeks to help you with. You cannot afford to miss a single point here. Take all distractions away and enjoy the best information you need about misfires.
What is an Engine Misfire?
To start with, a misfire is an engine problem. It mostly happens on cylinders. For a car engine to operate correctly, it needs to burn fuel, which requires oxygen to mix with it, a powerful spark to kick it to start, and an exhaust to blow out burnt fuel. This is the whole scenario that happens in the engine when the ignition is turned on.
Now a misfire usually happens when one of these components is missing or happens in the wrong order. The burning fuel needs to mix with oxygen in the cylinder for the pistons to revolve, and most cars have four cylinders that work simultaneously in sequential order. Hence, a failure in the fuel-air mixture ratio will lead to a misfire.
When this order is not followed on each cylinder, it can lead to a misfire, negatively impacting the car’s performance. A misfire can happen on one cylinder or in all cylinders, depending on the severity of the problem.
When a misfire happens, you will notice that your car engine is not working properly, even if the car is working. But there are crucial signs to look out for, as an increase in the release of emissions, higher fuel consumption, and possibly an unpleasant sound, among others.
Signs & Symptoms: Engine Misfire
As earlier stated, there are different signs that your car engine is misfiring, and the ability for you to notice these signs early is imperative for your car’s survival. Below are some of the general indications of a misfire.
Changed Engine Sound
This is the first and most common symptom of a misfiring engine. Your car is powered by a four-cylinder engine that produces a unique sound that you are used to when you turn on the ignition and when the car is running. Then a misfire happens in one of the cylinders; you will notice a deviation from the sound you are used to.
Check Engine Light
Just like every other indicator like seat belts, the airbag on, door open, and many others. There is also an indicator for your engine’s health, the “check engine.” This indicator tells you that something is wrong with your engine that you should have checked out. Since a misfire is an engine issue, this light will notify you so you can make necessary repairs.
Another symptom of a misfire is an increase in the release of smoke from the car’s exhaust. This happened due to the incomplete combustion of the fuel that is supposed to be burnt off during engine operation.
Accelerating and switching to a higher gear on a misfiring engine is quite rough. You will notice twitch or hesitation by the engine when you want to increase speed. More so, changing your gear will become harder with a misfiring engine.
The incomplete combustion of fuel and heat produced due to the load on the other engines that may not be misfiring will lead to the production of a foul smell.
Causes of an Engine Misfire
A misfire of an engine is simply the failure of an engine to properly discharge (ignite) because of issues like a failed spark, incomplete fuel combustion, and other causes. From there, you can attribute a number of things to a misfire in an engine.
Primarily, a misfire is caused by a poor ignition system and the inability of fuel to burn completely. However, other things lead to the failure of these systems. They include;
Spark Plug Issues
Spark plugs provide power for ignition to occur. A worn-out, rusty, dirty, or not properly plugged spark plug may lead to a misfire. The spark plug not igniting the fuel-air mixture at all or at the wrong time will lead to a change in the sequential order of the ignition process, which is a cause of a misfire of an engine.
Bad Fuel Filter
The fuel injection system supplies fuel that mixes with oxygen during ignition. A bad or clogged fuel injector will lead to less or no supply of fuel to the engine’s cylinders, which may lead to a misfire. Since the fuel supply is to all the cylinders of an engine, not getting enough or no fuel at all will affect not just one cylinder but all the cylinders. This is known as a lean misfire. Additionally, a leaking gasket can lead to a misfire.
Worn-out Ignition Coil & Wires
The ignition coil is also called the spark coil. It is needed to transfer electric sparks to a spark plug for ignition to occur. Therefore, a bad ignition coil will lead to a misfiring engine.
Pistons & Bearings
The piston is the revolving part found in a cylinder that provides the energy that powers the movement of the wheels of a car. A stiff or broken piston in a cylinder will cause an engine to misfire.
How to Fix an Engine Misfire?
To fix a misfire, you need first to know the cause of the misfire. It could be a faulty spark plug, a bad ignition coil, or the fuel systems. A spark plug is easy to fix; if it’s a bad plug, all you have to do is replace it. If it is a misplaced plug, you can properly install them. For the fueling system, bad coil, and broken piston, you refer to an expert.
As I noted earlier, one of the first things you notice when there is a misfire is that one of your engine cylinders will fail to work properly. Also, your auto engine will not run on balance and that will lead to strong vibration that often occurs in your car body and affects it.
While it may be difficult to point to the causes of the misfire, fixing it is not as difficult. Although it may require you to carry out some repairs, you will still solve a misfire issue without any special tools or skills. You will not have to break the bank either.
Let’s take a look at the four-step process to fix a misfire problem:
1. Identify the Problem
The check engine light is the first suspect when there’s a misfire. It will always turn on as the engine misfires. It goes off as the misfire stops. Look for other signs (as listed above) apart from the flashing of the check engine light.
With an OBDII scanner, identifying the issues is easy. Simply plug the scanner, and it’ll help you identify the specific or general error to the misfiring cylinders.
2. Carry Out a Compression Diagnosis
You will also have to do a compression test to know if there is a synergy between spark, fuel, and air. To do this, you’ll need to remove the fuel pump-powering fuse before pulling out the spark plugs. In place of the spark plugs, rivet a compression tester and turn it to allow the engine to turn over a couple of times. The reading on your compression gauge will be at its peak.
Take this process again on each of your engine cylinders, and you can be sure that the figures on your gauge will be the same. This means that the misfire is not due to the compression issue. Otherwise, you will notice a difference in reading if the misfire is a result of the lack of compression.
3. Fix Compression Issue
Because faulty piston rings cause a lack of compression, which can lead to engine misfire, there is a need for a lack of compression. You will need to inspect the base of your engine. To eliminate compression issues, allow the free flow of the oil through the cylinder. In that case, you’ll need to take off and replace the cylinders, connecting rods, and crankshaft.
In another instance, the head gasket may cause a lack of compression. In the case of a faulty head gasket, you’ll notice some coolant mixing up with your oil. In that case, you’ll need special skills and tools. To avoid further damage, hiring a professional technician will be the best bet.
4. Carry Out Coil Pack Test & Replace If Faulty
You will also need to know if there is a fault with the coil pack. To do this, use your ohmmeter to determine if the spark plugs will make the air-fuel mixture ignite. If there is no ignition, then you can be sure there is a fault with your coil pack and that can cause a misfire. You will need to disconnect the wiring by removing the coil from the bracket before fixing a new one.
Frequently Asked Questions
Q: How much will I spend to fix a misfire?
There is no cast-in-stone rule about this. There are a lot of factors that go into determining how much it will cost you to fix your car’s engine misfiring. You have to consider the age of your car. Besides, the misfiring problem will also inform how much you will spend. An issue with the ignition coil on a newer engine won’t come at the same cost if your car works with an old engine. If you spend $300 on old cars, you will pay a little more ($400) on newer models. Even though fixing misfiring issues is easy, replacing the parts may take some money from you.
Q: Can I drive a misfiring car?
A misfire might be caused by a simple issue like a bad spark plug. However, if you choose to drive a misfiring car, you may cause further and more severe damage to the engine, which will be detrimental to your car and your pocket. The safest thing to do is to park a car that is running on a misfiring engine.
Q: Can a low oil level cause a misfire?
It depends, but technically speaking, a low oil level in your car engine may not cause an engine misfire. However, when you notice that the oil pressure light illuminates and your car engine has low oil pressure, the misfire you’re experiencing is likely caused by low oil levels. To avoid suspicion, you need to ensure the scheduled maintenance of your engine. Make sure your engine has enough oil to prevent engine wear and malfunction.
A misfire can be a little issue, but if you don’t quickly jump into action it may escalate into something that will be beyond DIY control. This is why you must pay close attention to every symptom your car shows.
To adequately tackle a misfire, it begins with you noticing indications that the engine is misfiring. So, you must know your car so well that little changes will be suspicious to you.
From this post, you can offer a direct answer the next time someone asks you what a misfire means.
- What Causes Backfire Through Intake?
- Waxing Car Windows: Is It Worth It?
- Transfer Case Fluid: How Often & What Is It?
- Rubbing Compound: What Is It & How To Use
- Gear Shift Stuck: A Complete Guide
- Symptoms of a Failing or Bad Fuel Filter
- P0700 Trouble Code: A Complete Guide
- Driving With Tire Bulge: Causes & Is It Safe?