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P0306 Chevrolet Code - Cylinder 6 Misfire Detected

Quick Answer

When a Chevrolet vehicle's onboard diagnostics system detects a misfire in cylinder 6, it triggers trouble code P0306. Common causes include Faulty spark plug or ignition coil, Clogged fuel injector, Vacuum leak. 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
P0306 Chevrolet indicates Cylinder 6 Misfire Detected.
Common causes
Common causes include Faulty spark plug or ignition coil, Clogged fuel injector, Vacuum leak.
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 P0306 Chevrolet Description

When a Chevrolet vehicle's onboard diagnostics system detects a misfire in cylinder 6, it triggers trouble code P0306. This means that the engine is not running smoothly, leading to a lack of power, rough idle, and potential damage to the catalytic converter. A misfire occurs when the air-fuel mixture in the cylinder fails to ignite at the right time, causing a disruption in the combustion process. This can be caused by issues such as a faulty spark plug, ignition coil, fuel injector, or a vacuum leak. If left unaddressed, a cylinder misfire can lead to decreased fuel efficiency, engine damage, and even complete engine failure.

OBDII Code P0306 Chevrolet - Cylinder 6 Misfire Detected
P0306 Chevrolet Code - Cylinder 6 Misfire Detected

Common Causes of P0306 Chevrolet

  1. Faulty spark plug or ignition coil
  2. Clogged fuel injector
  3. Vacuum leak
  4. Low compression in cylinder 6
  5. Ignition timing issues

Symptoms of P0306 Chevrolet

  1. Rough idle
  2. Loss of power
  3. Engine vibration
  4. Increased fuel consumption
  5. Check Engine Light illuminated

How to Fix P0306 Chevrolet

  1. Diagnose the specific cause of the misfire by performing a compression test, checking the spark plug, ignition coil, and fuel injector in cylinder 6.
  2. Replace the faulty component, whether it be a spark plug, ignition coil, fuel injector, or address any vacuum leaks.
  3. Clear the trouble code and reset the Check Engine Light.
  4. Test drive the vehicle to ensure the issue has been resolved.
  5. Perform a follow-up scan to confirm that the misfire has been successfully addressed.

Cost to Fix P0306 Chevrolet

The cost of repairing a cylinder 6 misfire on a Chevrolet can vary depending on the specific cause of the issue. On average, the parts required for this repair could range from $50 to $200, with labor costs adding another $100 to $300. This estimate does not include diagnostic fees, taxes, or any additional parts or services that may be needed. It's recommended to consult with a trusted mechanic or auto repair shop for a more accurate cost estimate based on your vehicle's make and model.

What does this mean?

Tech Notes for P0306 Chevrolet

The P0306 code means that cylinder 6 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 6. If the problem persists more tests needs to be done to diagnose the problem, see "Possible Causes".

There is a Factory Service Bulletins for All 2000-2020 Chevrolet Models:
2000-2020 Chevrolet Factory Service Bulletin OBDII Code P0306
This Factory Service Bulletin explains how this condition may be caused by significant carbon build-up on the intake and/or exhaust valves due to fuel contamination or incomplete burning of the fuel.

P0014 / P0306 2002 Trailblazer




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Information for Specific Chevrolet Models

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 P0306 Chevrolet Code

1. What are the common symptoms of OBDII code P0306 in a Chevrolet, indicating a Cylinder 6 misfire?

- Common symptoms include engine vibration, loss of power, rough idle, and potentially increased fuel consumption.

2. What are some possible causes of a Cylinder 6 misfire in a Chevrolet triggering code P0306?

- Causes may include faulty spark plugs, ignition coil issues, a clogged fuel injector, vacuum leaks, or problems with the engine's compression.

3. How can I diagnose the specific cause of the Cylinder 6 misfire triggering OBDII code P0306 in my Chevrolet?

- Diagnostic steps may involve checking the spark plug, ignition coil, fuel injector, vacuum lines, and performing a compression test to pinpoint the issue.

4. Can driving with OBDII code P0306, signaling a Cylinder 6 misfire in a Chevrolet, cause damage to the vehicle?

- Continuing to drive with a misfire can potentially damage the catalytic converter over time and may lead to further issues with the engine.

5. Are there any simple repair tips I can try to fix the Cylinder 6 misfire associated with OBDII code P0306 in my Chevrolet?

- You can start by inspecting and replacing the spark plugs, ignition coil, or cleaning/replacing the fuel injector for Cylinder 6 to see if that resolves the misfire.

6. What are the recommended steps for repairing a Cylinder 6 misfire in a Chevrolet triggering OBDII code P0306?

- Proper repair may involve replacing the spark plugs, ignition coil, fuel injector, performing a compression test, and addressing any vacuum leaks to resolve the misfire issue.

7. How important is it to address OBDII code P0306 indicating a Cylinder 6 misfire in a Chevrolet promptly?

- It is crucial to address this issue promptly to prevent potential damage to the engine, ensure optimal performance, and maintain fuel efficiency.

8. Can a DIY enthusiast fix the Cylinder 6 misfire causing OBDII code P0306 in a Chevrolet, or should it be left to a professional mechanic?

- Depending on your skill level and access to tools, some DIY enthusiasts may be able to address the misfire issue, but if unsure, it is recommended to seek help from a professional mechanic.

9. Will resetting the OBDII code P0306 for a Cylinder 6 misfire in a Chevrolet make the issue go away permanently?

- Simply clearing the code without addressing the underlying cause will not fix the problem; it's crucial to diagnose and repair the root issue to prevent the misfire from recurring.

10. What is the typical cost to repair a Cylinder 6 misfire linked to OBDII code P0306 in a Chevrolet at a mechanic or dealership?

- The cost can vary depending on the exact cause of the misfire, but it may range from a few hundred dollars to over a thousand dollars, including parts and labor.

Discuss the causes and fixes for P0306 Chevrolet OBDII Code

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  • I have code p0306 and have tried swapping coil packs wires and plugs has enough spark to shock me but not enough to show with a wire tester it is an 08 chevy Silverado lc9 5.3

    Reply to Comment

  • A friend of mine has a 2015 Chevy Silverado, 5.3L, with 122K miles that was bought new and serviced by the book. It runs rough at start-up and continues at running temp. The code reader showed P0306. He replaced the plugs, plug wires, coils, and injectors. Nothing helped, so he took it to a local shop. Their diagnosis was a bad lifter. I`m not convinced! They did not do a compression test and there is no noise (tapping or clicking) coming from the engine. What do you think?

    Reply to Comment

  • I doubt is the filter, if the problem was the filter, then more than one cylinder will be misfiring. There is a factory service bulletin for a similar problem.

    2000-2018 Chevrolet Factory Service Bulletin OBDII Code P0306

    This Factory Service Bulletin explains how this condition may be caused by significant carbon build up on the intake and/or exhaust valves due to fuel contamination or incomplete burning of the fuel.

    Reply to Comment