AutoCodes – Infiniti – P0303 2005 Infiniti G35

P0303 2005 Infiniti G35 Code - Number 3 Cylinder Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3. 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: P0303 2005 Infiniti G35 indicates Number 3 Cylinder Misfire Detected.
Common causes: Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3.
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 6,600

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 Mar 29, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0303 2005 Infiniti G35 Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring. The Diagnostic Trouble Code (DTC) will be set when the Engine Control Module monitors the crankshaft speed and has detected that engine cylinder #3 is misfiring.

OBDII Code P0303 2005 Infiniti G35 - Number 3 Cylinder Misfire Detected - AutoCodes.com — P0303 2005 Infiniti G35 Code - Number 3 Cylinder Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0303 2005 Infiniti G35?

Faulty Spark Plug #3
Clogged or faulty Fuel Injector #3
Faulty Ignition Coil #3
Fuel Injector #3 harness is open or shorted
Fuel Injector #3 circuit poor electrical connection
Ignition Coil #3 harness is open or shorted
Ignition Coil #3 circuit poor electrical connection
Insufficient cylinder 3 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0303 2005 Infiniti G35?

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 P0303 code means that cylinder #3 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 #3. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 2005 Infiniti G35 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.

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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 P0303 2005 Infiniti G35 Code

1. What are common symptoms of OBDII code P0303 (Number 3 Cylinder Misfire Detected) in a 2005 Infiniti G35?

- Common symptoms include engine misfiring, rough idling, loss of power, and potential increase in fuel consumption.

2. What are the typical causes of OBDII code P0303 in a 2005 Infiniti G35?

- The code P0303 is usually caused by issues such as faulty spark plugs, ignition coil failure, vacuum leaks, or problems with the fuel injector.

3. How can I diagnose the source of a misfire in the number 3 cylinder of a 2005 Infiniti G35?

- You can perform diagnostic tests such as checking spark plugs, inspecting ignition coils, conducting a compression test, and scanning for other trouble codes.

4. Can a dirty fuel injector cause OBDII code P0303 in a 2005 Infiniti G35?

- Yes, a dirty or clogged fuel injector can disrupt the air-fuel mixture and lead to a misfire in the number 3 cylinder, triggering code P0303.

5. Are there any simple DIY repair tips for addressing OBDII code P0303 in a 2005 Infiniti G35?

- DIY repair tips include checking and replacing spark plugs, inspecting ignition coils for damage, cleaning or replacing the fuel injector, and ensuring proper fuel pressure.

6. How important is it to address OBDII code P0303 promptly in a 2005 Infiniti G35?

- It is crucial to address code P0303 promptly to prevent potential damage to the catalytic converter, decrease in fuel efficiency, and further engine performance issues.

7. Can driving with OBDII code P0303 in a 2005 Infiniti G35 cause long-term damage?

- Continued driving with a misfire detected in the number 3 cylinder can lead to more severe engine problems, reduced engine lifespan, and increased repair costs.

8. Is it recommended to reset the OBDII code P0303 in a 2005 Infiniti G35 after addressing the underlying issue?

- Yes, it is advisable to reset the code after fixing the problem to clear the Check Engine Light and monitor if the issue reoccurs during driving.

9. How can a professional mechanic help with diagnosing and repairing OBDII code P0303 in a 2005 Infiniti G35?

- A professional mechanic can perform advanced diagnostic tests, accurately pinpoint the cause of the misfire, and provide expert repairs to ensure the issue is resolved effectively.

10. Can extreme weather conditions affect the occurrence of OBDII code P0303 in a 2005 Infiniti G35?

- Yes, extreme weather conditions like extreme cold or heat can impact the engine's performance and contribute to misfires, potentially triggering code P0303.