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Engine-Codes – Generic – P0301

P0301 Code - Cylinder 1 Misfire Detected

Quick Answer

When the OBD-II system detects a misfire in cylinder 1, it means that the fuel-air mixture in that particular cylinder is not igniting properly. Common causes include Faulty spark plug, Failing ignition coil, Clogged or malfunctioning fuel injector. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0301 indicates Cylinder 1 Misfire Detected.
Common causes
Common causes include Faulty spark plug, Failing ignition coil, Clogged or malfunctioning fuel injector.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0301 Description

When the OBD-II system detects a misfire in cylinder 1, it means that the fuel-air mixture in that particular cylinder is not igniting properly. This can lead to a rough idle, decreased fuel efficiency, loss of power, and potentially cause damage to the catalytic converter over time. The misfire can be caused by issues such as a faulty spark plug, ignition coil, fuel injector, vacuum leak, or low compression in the cylinder. Ignoring this code can lead to further engine damage and result in costly repairs in the long run.

OBDII Code P0301 - Cylinder 1 Misfire Detected
P0301 Code - Cylinder 1 Misfire Detected

Common Causes of P0301

  1. Faulty spark plug
  2. Failing ignition coil
  3. Clogged or malfunctioning fuel injector
  4. Vacuum leak in the intake manifold
  5. Low compression in cylinder 1

Symptoms of P0301

  1. Rough idle
  2. Engine hesitation or stumbling
  3. Loss of power
  4. Increased fuel consumption
  5. Illumination of the Check Engine Light

How to Fix P0301

  1. Use an OBD-II scanner to confirm the misfire in cylinder 1.
  2. Inspect and replace the spark plug in cylinder 1.
  3. Check and replace the ignition coil if necessary.
  4. Clean or replace the fuel injector for cylinder 1.
  5. Perform a compression test to check for low compression in cylinder 1.

Cost to Fix P0301

The typical repair cost for addressing a cylinder 1 misfire detected code can range from $100 to $500, depending on the specific cause of the issue and the cost of parts and labor in your area. Keep in mind that additional diagnostic time and labor costs may apply, so it is recommended to consult with a mechanic for an accurate estimate.

What does this mean?

Tech Notes for P0301

The P0301 code means that cylinder 1 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 1. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".













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Code P0301 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0301 Code

1. What are the common symptoms of OBDII code P0301 (Cylinder 1 Misfire Detected)?

Symptoms may include engine misfiring, rough idling, loss of power, increased fuel consumption, and potentially a noticeable decrease in acceleration.

2. What are the possible causes of OBDII code P0301 (Cylinder 1 Misfire Detected)?

Common causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the engine control module.

3. How can I diagnose the cause of OBDII code P0301?

Diagnosing the issue may involve conducting a visual inspection of spark plugs and ignition components, performing a compression test, checking for vacuum leaks, and using a scan tool to monitor live data from the engine.

4. Can driving with OBDII code P0301 (Cylinder 1 Misfire Detected) damage my engine?

Continuing to drive with a misfire can potentially cause damage to the catalytic converter, oxygen sensors, or other engine components over time. It is advisable to address the issue promptly.

5. How can I repair OBDII code P0301 (Cylinder 1 Misfire Detected)?

Repair steps may include replacing spark plugs, ignition coils, or fuel injectors, repairing vacuum leaks, addressing low compression issues, or updating the engine control module software.

6. Is it safe to continue driving with OBDII code P0301 if the symptoms are intermittent?

While intermittent symptoms may not pose an immediate danger, it is still recommended to address the underlying issue as soon as possible to prevent potential long-term damage to the engine.

7. Can bad gasoline cause OBDII code P0301 (Cylinder 1 Misfire Detected)?

Low-quality or contaminated gasoline can contribute to misfires, so it's important to use fuel from reputable sources and consider adding a fuel system cleaner if needed.

8. Will resetting the OBDII code P0301 clear the issue?

Resetting the code may temporarily turn off the check engine light, but it will not fix the underlying problem causing the misfire. It's best to diagnose and repair the issue to prevent it from recurring.

9. How long does it typically take to repair OBDII code P0301 (Cylinder 1 Misfire Detected)?

The repair time can vary depending on the exact cause of the misfire. Simple fixes like replacing spark plugs may take less than an hour, while more complex issues could require several hours or more.

10. Can extreme weather conditions trigger OBDII code P0301 (Cylinder 1 Misfire Detected)?

Extreme cold or hot weather can sometimes exacerbate existing issues with spark plugs, ignition components, or fuel delivery, potentially leading to a misfire and triggering the P0301 code.

Discuss the causes and fixes for P0301 OBDII Code

Submit a New Comment

  • Had same problem with month old reman heads, it was a broken intake valve spring.

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  • i have this problem tre times, have reset and change sparkplug one time, but get it back the same trouble, after last of time reset have its been better, i think the trouble its the coil

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  • What model and year is your vehicle? ignition coils are very common problem.

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  • Models of CA 33 ( 00-03)

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  • Could you be a bit more specific? make and model?

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  • this its a model of 00 -03 Maxima

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  • The ignition coils are very,very common problem on the Maxima. We replace ignition coils almost every week on Nissan vehicles. If there is an excessive fuel smell from the tail pipe, then it means that the problem is the fuel injector. Since you have P0301 code, then the problem is either ignition coil #1 or fuel injector #1

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  • My 08 Altima coupe was washed just like his but I didn't cover anything up. Had the shuttering and misfire cylinder 1 code and have replaced w high quality spark plugs. Ran badass for a an hour just went back out and it's there again. No engine light yet. I'm thinking th 1 ignition coil but idk.. any ideas? No prev problems 134k 4cyl

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  • Yes, sounds like a bad ignition coil.

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  • I have a 2005 Malibu maxx….Codes po301 and po455 came up yesterday. 4 months ago I just had a tuneup with new plugs, boots and wires. 2 months ago I had these codes for plug number 6. last month one of the hoses got caught in something and completely came off. now this. its neverending. I replaced the transmission already along with a lot of other things. should I keep putting money into this, tranny has less than 70,000 and I doubt its going to pass inspection come oct. its getting very rusty

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  • The P0301 code is related to the spark plugs repair. I recommend taking you vehicle back to the shop that replaced the spark plugs and wires.

    The P0455 code may not be related to the P0301. It could be just a loose or missing gas cap.

    P0455 CHEVROLET - Evaporative Emission Control System Leak Detected Gross Leak
    Read more: https://www.autocodes.com/p...

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