P0305: What You Need To Know About Engine Misfires

P0305: What You Need To Know About Engine Misfires

You do not have to be a mechanic to make a quick diagnosis of your car. It is possible to find out the problems in your car once you notice any unusual behavior. All you need is a proper tool that can help you pinpoint the issue. You do not have to possess vast knowledge about car engines to detect a problem. Your vehicle itself is quite helpful when it comes to diagnosing. Are you worried about the P0305 trouble code that just showed up in your car? Here is all you need to know about this code and what it means!

OBD-II scanners are used for reading these trouble codes. If you have an OBD-II scanner at home, you can make a quick diagnosis of the car anytime you feel there might be some problem with the vehicle. They are not that expensive. It is easy to operate a scanner, and you can look up the trouble codes to know what each of them means.

The P0305 trouble code indicates that there is a misfire in one of the cylinders in the car engine. Once you know the trouble code, you can expect what the causes of that issue are. Then you can move on to solving the issue. In this post, we will discuss all there is to know about the P0305 code and how to deal with it.

P0305 Code

Any trouble code in a vehicle indicates just what you would expect: trouble. When you see the engine check light flashing, expect to find something wrong with the vehicle. The problem becomes much clearer once you read the trouble code. All the codes are different and they are a useful system that helps detect any machinery problem.

The P0305 trouble code indicates a misfire in cylinder number 5. If any one of the cylinders is malfunctioning, it will cause the car engine to malfunction as well. The code itself may not be enough to pinpoint the exact issue, but it is enough to give you an idea of what to expect.

If you tell any mechanic, that a P0305 cylinder with 5 misfires is detected, it will save a lot of time. A quick diagnosis or a reading of the code is not enough to solve the issue of a misfiring cylinder. There are several possible reasons for a cylinder to misfire. A mechanic has to assess the car properly to figure out the exact reason for the misfire so they can solve it.

Some of the most common reasons include worn-out spark plugs or any leaks in one of the internal components. But you should expect to find other issues and be prepared to pay for the necessary repairs.

(Watch this video to learn about how to fix code P0305).

P0305 Cylinder 5 Misfire Detected

Trouble code P0305 means that there is a misfire in engine number 5. The last number on the code points to the cylinder number. No matter what type of vehicle you drive, you can encounter this code at any time. Let us give you an idea about what to expect with code P0305 for different vehicles.

P0305 Ford Code

It is very common to stumble upon the trouble code P0305 Ford F150. The Ford F150 is a beloved truck. It is a reliable vehicle that a lot of people prefer. While determining the cylinder 5 location, keep in mind that it will be the fifth cylinder in the firing order. Do not assume it is the fifth engine you find while inspecting the engine.

P0305 BMW Code


The P0305 code implies that cylinder 5 is misfiring continuously or erratically. First, check for intake leaks. If there are none to be discovered, replace the spark plugs on cylinder 5. That should help with the issue. When there is a misfire, the engine speed varies. The Engine Control Module (ECM) can detect a misfire if the engine speed varies enough to trigger the crankshaft position sensor signal to shift.

P0305 Dodge Code

P0305 is a cylinder-specific error code, which makes identifying the problem easier than P0300. The later code indicates that the cylinders are randomly misfiring. The number 5 at the end tells us the number of the cylinder. The labor hour for fixing a P0305 Dodge code should be 1 hour.

P0305 Chevy Code

Examine and test the ignition system components surrounding the engine to see whether the coil packs, spark plugs, or wires need to be replaced. In most cases, one of these three factors will be the root of the problem.

How To Read Trouble Codes?

Diagnostic Trouble Code, also known as the DTC, is a great way of singling out what is causing a vehicle to act up. A DTC code can identify any machinery problem, whether it is a vehicle or equipment. The engine checks light of a car will flash when there is any problem within the car. Once you read the DTC code, you will know what to do.


On-board Automotive Diagnostics is also known as OBD. An OBD-II scanner is used to read a DTC or trouble code. To read the trouble codes, insert a scan tool or code reader into the OBD-II diagnostic port. You can probably find it beneath the dashboard near the steering column. The scanner will then reveal the code(s) that caused your car check engine light to flash.

Even if you do not know how to read the codes, just knowing them is enough to ease your mind. Most of the trouble codes you will encounter will start with a “P.” The “P” stands for the powertrain. The P codes are often responsible for flashing the check engine light.

With an OBD-II scanner at hand, you can connect it to your car and read the codes anytime. You can buy an OBD-II scanner if you do not have one already. They are quite affordable and can be a lifesaver at times.

What Are The Symptoms Of Code P0305?

Aside from the flashing check engine light telling you there is something wrong with the vehicle, there are other symptoms to look out for. These symptoms are more commonly associated with the trouble code P0305.

  • Check engine light is on
  • Engine jerking or rough sounds during acceleration
  • Fuel economy decreases
  • The engine does not supply enough power
  • Fuel smell emitting from the exhaust
  • Problem with acceleration
  • Car dies at stop signs or while braking

Even if you do not notice any of these symptoms, that does not mean your car is perfectly healthy. Engine misfires can either be small or big. Although severe misfires are more noticeable, it is possible to miss a small one. But you should not ignore a small misfire and brush it aside as nothing.

If the P0305 code is evident, make sure you look into it. A small misfire in the engine can turn into a much bigger problem in the future if you leave it unattended. If you do not address the problem when it is still a minor one, it will end up costing you a fortune if you let it rest.

Cylinder 5 Misfire Causes

After reading the trouble code P0305, it is understandable to be curious. You might want to know what is causing your car to act up. Whether it is out of curiosity or to gain some knowledge, you should learn what is under the hood. If you understand your vehicle better, you can treat it better as well.

Fuel, sparks, and oxygen – an issue with any three of these components in a vehicle can cause a misfire in a cylinder. That will lead to a trouble code P0305 which means a misfire in cylinder number 5. Once the code is detected, it is not hard to understand what the problem might be.

There are a handful of situations that will lead to a cylinder misfire. Take a look at this list of cylinder 5 misfire causes, so you know what to look out for.

When you detect code P0305, you should expect to find any one of these problems in your vehicle. You can do a diagnosis at home if you have the proper tools and knowledge. The best step is to take the car to the workshop or call a professional mechanic right away.

How Serious Is Code P0305?

A P0305 trouble code is pretty serious. So it would be wise not to ignore it after you detect the code in your vehicle. A misfire in one of the cylinders in your engine might seem like a minor problem. But it is a big concern, and if left unattended, the result will be disastrous.

You might notice performance issues with the engine after detecting the P0305 code. There can be acceleration problems, fuel leaks, and more. Any one of these problems can affect your driving. It is very risky to drive a car with a faulty cylinder. If your car stalls in the middle of the road, you can end up crashing it.

If you do not fix the trouble code and take your car to the mechanic, the misfires will continue. Repeated misfires in a cylinder can cause the engine to be severely damaged. A faulty spark plug or even a vacuum leak will cost you much less compared to an engine replacement.

Is It Safe To Drive With Code P0305?

When you know your car dashboard is flashing the check engine light because of code P0305, you should stop driving the car. A misfire in cylinder number 5 is the reason for the P0305 code. It is not safe to drive around in a car that has a faulty cylinder.

Since the cylinder misfire can be an indication of severe engine problems, your car is unreliable for the road. Even small symptoms such as engine sputtering, jerking, bad fuel smell, and more can be quite annoying. Any unwanted behavior from your car, while you are on the road, can be distracting. Such distractions can often cause accidents to happen, especially when you are on the highway.


Fuel efficiency can drop when the cylinder is misfiring. If the fuel efficiency decreases, you will end up visiting the gas station far more often than normal. Your fuel cost will increase noticeably. To avoid any one of these unwanted situations, do not drive your car once you detect trouble code P0305.

Do whatever you can to resolve the issue. Even if you know to inspect the problem, it would be best to get the car looked over by a professional mechanic as soon as possible. In the meantime, avoid driving the car unless it is an emergency.

How To Fix Code P0305?

There is huge diversity in the vehicle brands and models for us to determine a universal way of fixing the P0305 code. The reasons behind the code being triggered can be very different as well. It would be impossible for you to fix the code if you have zero knowledge of car trouble codes.

Even with proper knowledge and tools, it is not advisable to deal with this code at home. But if you have some mechanic experience under the belt, you can try fixing the code yourself. Otherwise, take the car to a workshop as soon as you can.

A mechanic will first apply a code reader to understand the problem. Whether the spark plug is the cause, a mechanic will power the engine at idle to test. Then they will remove the leads from the coil pack to determine if any wire is a concern.

Spark plugs are often the reason behind code P0305. They are very cheap. So if you think the spark is at fault, consider replacing the offending component at once. If the ignition and timing components have been cleared out, you can go on to the less probable issues such as faulty sensors, fuel pressure, or other technical problems.

(Here is a video on how to quickly fix a trouble code P0305).

Cylinder Misfire Repair Cost

It is difficult to give an estimated cost for the repairs of a P0305 code without figuring out the problem. There are several possible reasons for a car to reveal the P0305 trouble code. The bigger the issue is, the more cost you will have to bear.

Once you know the trouble code, consult a professional to inspect the car. They will find out the problems, and you will know whether or not the repairs will break the bank. A cylinder misfire repair cost is often a small number. If you are lucky, it can be just an issue with the spark plug. A new spark plug costs around $120-150.

But you may not be so lucky, and the issue can lie within the engine. Even a vacuum leak will end up costing you more than a thousand dollars.

For any problem with the spark plug, spark plug wires, ignition coil, fuel injector, or a faulty valve spring, it will cost you around $500. If there is a vacuum leak, a problem with fuel delivery, or the piston rings are at fault; you should be ready to pay $1,000-3,000 for the repairs.

These are the estimated cost for just the parts and repairs. You will have to pay diagnostic costs and service costs to the mechanic working on your car. That cost will vary depending on the workshop you take the car to.

Common Mistakes To Avoid While Fixing Code P0305

You can get rid of the trouble code by doing a quick reset and retesting. That might solve your problem temporarily, but it is not the best solution. The vehicle can fail to show any other symptoms that might indicate a cylinder misfire. That does not mean you should get rid of the trouble code by any means necessary and be done with it.

Small issues with the cylinder may not be as evident in the early stages. So it is advisable to conduct a proper diagnosis of the car at any chance you get. Some mechanics will immediately replace the spark plugs in your car as soon as the trouble code is revealed. They might also suggest getting a replacement of the ignition coil and being done with it.

Engine misfires

But doing these will not always solve the issue of code P0305. Without making a full diagnosis of the car, it is impossible to know whether or not there are other issues in the cylinder or the engine itself. It is crucial to be aware of these situations. Routine maintenance of your system’s hoses, wiring, and valves can assist you in preventing such issues from occurring.

Neglecting to make a full diagnosis can lead to underlying issues with the car. If you continue driving the car with an undetected problem, the engine will be at risk. Continued misfires in the cylinder can be severe for the car engine if it is not dealt with soon. Misfires are often triggered by problems with the air-to-fuel ratio in the car.

These can be caused by leaks in the vacuum system, as well as blocked or leaking parts in the exhaust system.

Facts about Cylinder 5 Misfire (P0305) in a Car Engine

  1. OBD-2 (On-Board Diagnostic) codes are a part of a car’s self-diagnostic system used to indicate specific issues in the engine.
  2. P0305 is a generic OBD-2 code that indicates a misfire in cylinder 5 of the car engine.
  3. A cylinder is a chamber inside the engine where power is generated when gasoline burns, and most engines have 4-8 cylinders.
  4. The P0305 error is triggered when the crankshaft sensor detects a cylinder misfire and is set in ECM memory.
  5. Symptoms of a P0305 error include loss of power, unusual vibrations, rough engine running, and decreased fuel economy.
  6. Common causes of a cylinder 5 misfire are faulty spark plugs, ignition coils, leaking head gasket or vacuum leak, malfunctioning fuel injector, or bad fuel quality.
  7. Diagnosing and fixing a P0305 error requires at least intermediate mechanical knowledge and specialized equipment, and it’s not recommended for beginners to attempt to fix it.
  8. Fixing a cylinder 5 misfire can cost anywhere between $80 to $1900, depending on the root cause of the problem.
  9. It’s not safe to drive when a P0305 error is active as it can cause further engine damage and ignition failure.
  10. An engine misfire cannot fix itself, and ignoring the problem can lead to heavier bills from the mechanic.


Here are some popular FAQs:

How Do I Fix Code P0305

Code P0305 means a misfire in one of the cylinders in the engine. After knowing the trouble code, the car should have a full diagnosis to figure out what is causing the cylinder or the engine to misfire. The reasons can be anything from a faulty fuel system, a worn-out spark plug, or a malfunction in the ignition. Once you get enough information about what is causing the problem, then you seek repairs accordingly. Take your car to the workshop to find out what the issue is and fix the misfire as soon as you can.

What Is Code P0305

P0305 is a trouble code received from the OBD-II scanner. The code is an indication of detecting a misfire in one of the cylinders of the engine. The Engine Control Module, also known as ECM, detects this problem in a car, and the OBD-II scanner uses the P0305 code to designate the cylinder misfire.

What Does Code P0305 Mean

The DTC trouble code P0305 means there is a misfire in cylinder 5. The car engine can misfire or splutter if this code is detected. Instead of driving a car with this trouble code flashing at you every time you turn the ignition, get it fixed. It will help avoid risky situations.

How Much Does It Cost To Fix A Misfire

It depends on the damage that is causing the misfire. The cost to fix a misfiring cylinder can be anywhere from $150 to over $2,000. There are different qualities of spark plugs used in different vehicles. Spark plug wires, ignition coils, piston rings, and more can be part of the repair. Your mechanic will give you an estimated cost after making a full diagnosis.

Can A Vacuum Leak Cause A Misfire

Any vacuum leak can cause extra air to reach the cylinder if there is any vacuum leak. That can dilute the mixture of air and fuel more than is needed. As a result, the engine might stall abruptly and misfire. So yes, when there is a vacuum leak, you can expect misfires to happen as you drive the car.

Final Thoughts

Code P0305 is a rather common trouble code. People have to deal with this kind of issue all the time. Reading this particular code on an OBD-II scanner will not seem so scary if you know what to expect. There are a few possible causes for this code to show up.

Even though some of the reasons behind this code can seem unproblematic, it would be foolish to ignore it. Do not wait for your car to show signs of engine misfire or damage. As soon as you detect the code P0305, get your car diagnosed.

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