AutoCodes – Oldsmobile – P0308 Oldsmobile

P0308 Oldsmobile Code - Cylinder 8 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. Common causes include Faulty spark plug 8, Clogged or faulty fuel injector 8, Faulty ignition coil 8. 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 Oldsmobile indicates Cylinder 8 Misfire Detected.
Common causes: Common causes include Faulty spark plug 8, Clogged or faulty fuel injector 8, Faulty ignition coil 8.
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.

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Code Popularity 843

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 09, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0308 Oldsmobile Description

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. The Engine Control Module (ECM) can detect these variations by closely monitoring the crankshaft position sensor signal. The signals of the camshaft position sensors are used to determine which cylinder is misfiring. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, the Diagnostic Trouble Code (DTC) will be set. Under certain driving conditions, a misfire rate can be high enough to cause the catalytic converter to overheat, damaging the converter. The Malfunction Indicator Lamp (MIL) flashes when the converter is overheating, damaging conditions are present, and the DTC is set. The DTC will be set when the ECM detects a crankshaft rotation speed variation indicating a single-cylinder misfire rate sufficient to cause emissions levels to exceed mandated standards.

OBDII Code P0308 Oldsmobile - Cylinder 8 Misfire Detected - AutoCodes.com — P0308 Oldsmobile Code - Cylinder 8 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0308 Oldsmobile?

Faulty spark plug 8
Clogged or faulty fuel injector 8
Faulty ignition coil 8
Fuel injector 8 harness is open or shorted
Fuel injector 8 circuit poor electrical connection
Ignition coil 8 harness is open or shorted
Ignition coil 8 circuit poor electrical connection
Insufficient cylinder 8 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0308 Oldsmobile?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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".

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0308 Oldsmobile code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0308 Oldsmobile code?

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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 Oldsmobile Code

1. What are the common symptoms of OBDII code P0308 in an Oldsmobile indicating a Cylinder 8 misfire?

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

2. What are some possible causes of the Cylinder 8 misfire detected in an Oldsmobile with code P0308?

- Potential causes could include faulty spark plugs, a failing ignition coil, clogged fuel injector, vacuum leak, or issues with the engine's compression.

3. How can I diagnose the Cylinder 8 misfire issue indicated by OBDII code P0308 in my Oldsmobile?

- Diagnosis typically involves checking the spark plugs, ignition coils, fuel injectors, compression levels, and performing a thorough visual inspection of related components.

4. Can driving with OBDII code P0308 in an Oldsmobile be harmful to the vehicle?

- Continuing to drive with a Cylinder 8 misfire can potentially lead to further damage to the engine and components, so it's advisable to address the issue promptly.

5. What are some recommended repair tips for fixing the Cylinder 8 misfire detected in an Oldsmobile with code P0308?

- Repair tips may include replacing spark plugs, ignition coils, or fuel injectors, performing a compression test, checking for vacuum leaks, and ensuring proper engine timing.

6. Are there any DIY steps I can take to address the Cylinder 8 misfire in my Oldsmobile triggering OBDII code P0308?

- DIY steps may include inspecting and replacing spark plugs, checking ignition coils for signs of wear, cleaning or replacing fuel injectors, and looking for visible vacuum leaks.

7. How important is it to address the Cylinder 8 misfire issue flagged by OBDII code P0308 in an Oldsmobile promptly?

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

8. Can a dirty air filter cause the Cylinder 8 misfire detected by OBDII code P0308 in an Oldsmobile?

- A dirty air filter may not directly cause a Cylinder 8 misfire, but it can affect engine performance and contribute to other issues that lead to misfires.

9. Should I reset the OBDII code P0308 after addressing the Cylinder 8 misfire in my Oldsmobile?

- It is recommended to reset the code using an OBDII scanner after addressing the misfire issue to see if the problem has been successfully resolved.

10. Will fixing the Cylinder 8 misfire indicated by OBDII code P0308 in my Oldsmobile improve fuel efficiency?

- Addressing the misfire issue should help improve fuel efficiency by ensuring proper combustion in the affected cylinder, leading to better overall engine performance.