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Engine-Codes – GMC – P0308 2016 GMC Sierra

P0308 2016 GMC Sierra Code - Cylinder 8 Misfire Detected

Quick Answer

The diagnostic trouble code P0308 for a 2016 GMC Sierra indicates that a misfire has been detected in cylinder 8 of the engine. Common causes include Faulty ignition system components such as spark plugs, ignition coils, or spark plug wires, Clogged or dirty fuel injectors, Vacuum leaks in the intake manifold or hoses. 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
P0308 2016 GMC Sierra indicates Cylinder 8 Misfire Detected.
Common causes
Common causes include Faulty ignition system components such as spark plugs, ignition coils, or spark plug wires, Clogged or dirty fuel injectors, Vacuum leaks in the intake manifold or hoses.
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 Sep 15, 2024
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Code P0308 2016 GMC Sierra Description

The diagnostic trouble code P0308 for a 2016 GMC Sierra indicates that a misfire has been detected in cylinder 8 of the engine. A misfire occurs when the fuel-air mixture in the cylinder fails to ignite at the proper time, causing a disruption in the combustion process. This can lead to a lack of power, rough idling, poor fuel efficiency, and increased emissions.

OBDII Code P0308 2016 GMC Sierra - Cylinder 8 Misfire Detected
P0308 2016 GMC Sierra Code - Cylinder 8 Misfire Detected

Common Causes of P0308 2016 GMC Sierra

  1. Faulty ignition system components such as spark plugs, ignition coils, or spark plug wires
  2. Clogged or dirty fuel injectors
  3. Vacuum leaks in the intake manifold or hoses
  4. Low compression in cylinder 8 due to worn piston rings or valves
  5. Issues with the engine control module (ECM) or sensors such as the crankshaft position sensor

Symptoms of P0308 2016 GMC Sierra

  1. Rough idling or vibrations felt in the vehicle
  2. Loss of power or acceleration
  3. Engine misfiring or hesitation during acceleration
  4. Increased fuel consumption
  5. Check Engine Light illuminated on the dashboard

How to Fix P0308 2016 GMC Sierra

  1. Begin by diagnosing the specific cause of the misfire in cylinder 8 using a scan tool to identify the root issue.
  2. Inspect and replace faulty ignition system components such as spark plugs, ignition coils, or spark plug wires.
  3. Clean or replace clogged fuel injectors to ensure proper fuel delivery to cylinder 8.
  4. Check for vacuum leaks in the intake manifold or hoses and repair as needed.
  5. Perform a compression test on cylinder 8 to check for low compression and address any issues with worn piston rings or valves.

Cost to Fix P0308 2016 GMC Sierra

The cost of repairing a cylinder 8 misfire in a 2016 GMC Sierra can vary depending on the specific cause of the issue. On average, the cost of parts such as spark plugs, ignition coils, or fuel injectors can range from $100 to $500. Labor costs at auto repair shops typically range from $80 to $150 per hour, with the total repair bill potentially amounting to $200 to $800 or more. It's recommended to obtain quotes from local auto repair shops to get a more accurate estimate based on your location and vehicle specifics.

What does this mean?

Tech Notes for P0308 2016 GMC Sierra

The P0308 code means that cylinder 8 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 8. If the problem persists more tests need 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 P0308

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.

Need more information about the P0308 2016 GMC Sierra code?

Need more information on how to fix the P0308 2016 GMC Sierra code? Get Access to Factory Service Manuals

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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 P0308 2016 GMC Sierra Code

1. What does the OBDII code P0308 mean on a 2016 GMC Sierra?

P0308 indicates that the engine control module (ECM) has detected a misfire in cylinder 8 of the engine.

2. What are the common symptoms of a P0308 code in a 2016 GMC Sierra?

Symptoms include rough idling, reduced engine performance, poor fuel economy, check engine light illumination, and potential engine stalling.

3. What could cause a P0308 code on a 2016 GMC Sierra?

Possible causes include a faulty spark plug, a bad ignition coil, a clogged fuel injector, low compression in cylinder 8, or a vacuum leak.

4. Can bad fuel cause the P0308 code in a 2016 GMC Sierra?

Yes, contaminated or low-quality fuel can contribute to misfires, including in cylinder 8, and trigger the P0308 code.

5. How do I diagnose a P0308 code on my 2016 GMC Sierra?

Start by checking the spark plug and ignition coil for cylinder 8, inspect the fuel injector, and test cylinder compression. Use an OBDII scanner to confirm the misfire.

6. How serious is a P0308 code on a 2016 GMC Sierra?

It is moderately serious since it can lead to engine damage over time if not addressed, and it may cause a loss of power or efficiency.

7. Can I drive my 2016 GMC Sierra with a P0308 code?

While it may still be drivable, continued operation with a misfire can damage the catalytic converter or other engine components, so repairs should be made promptly.

8. What repairs typically fix a P0308 code on a 2016 GMC Sierra?

Common repairs include replacing the spark plug or ignition coil for cylinder 8, cleaning or replacing the fuel injector, and addressing any compression or vacuum issues.

9. Can a failing head gasket cause the P0308 code in a 2016 GMC Sierra?

Yes, a blown head gasket can lead to low compression in cylinder 8, resulting in a misfire and triggering the P0308 code.

10. How much does it cost to fix a P0308 code on a 2016 GMC Sierra?

The cost varies depending on the issue, ranging from $100 for a spark plug replacement to over $1,000 for more extensive repairs like fixing low compression or a head gasket.

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