Engine-CodesInfiniti – P0303 2003 Infiniti G35

P0303 2003 Infiniti G35 Code - Number 3 Cylinder Misfire Detected

Quick Answer

When a P0303 code is triggered in a 2003 Infiniti G35, it indicates that there is a misfire detected in the number 3 cylinder of the engine. Common causes include Faulty spark plug or ignition coil, Clogged or dirty fuel injector, Vacuum leaks. 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 2003 Infiniti G35 indicates Number 3 Cylinder Misfire Detected.
Common causes
Common causes include Faulty spark plug or ignition coil, Clogged or dirty fuel injector, Vacuum leaks.
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.
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0303 2003 Infiniti G35 Description

When a P0303 code is triggered in a 2003 Infiniti G35, it indicates that there is a misfire detected in the number 3 cylinder of the engine. This misfire can lead to a variety of issues that can affect the vehicle's performance, including rough idling, reduced power, decreased fuel efficiency, and potential damage to the catalytic converter over time. The misfire is typically caused by an imbalance in the air-fuel mixture, ignition system problems, fuel delivery issues, or mechanical problems within the engine. Ignoring this code can lead to further engine damage and costly repairs down the line.

OBDII Code P0303 2003 Infiniti G35 - Number 3 Cylinder Misfire Detected
P0303 2003 Infiniti G35 Code - Number 3 Cylinder Misfire Detected

Common Causes of P0303 2003 Infiniti G35

  1. Faulty spark plug or ignition coil
  2. Clogged or dirty fuel injector
  3. Vacuum leaks
  4. Low compression in the cylinder
  5. Engine timing issues

Symptoms of P0303 2003 Infiniti G35

  1. Rough idling
  2. Engine vibration
  3. Loss of power
  4. Poor acceleration
  5. Increased fuel consumption

How to Fix P0303 2003 Infiniti G35

  1. Begin by diagnosing the specific cause of the misfire by checking the spark plugs, ignition coils, fuel injectors, and compression in the number 3 cylinder.
  2. Replace any faulty spark plugs or ignition coils.
  3. Clean or replace clogged fuel injectors.
  4. Repair any vacuum leaks and ensure proper engine timing.
  5. Perform a compression test on the number 3 cylinder to check for any issues with compression.

Cost to Fix P0303 2003 Infiniti G35

The cost of repairing a P0303 code in a 2003 Infiniti G35 can vary depending on the specific cause of the misfire. Generally, the cost of replacing spark plugs or ignition coils can range from $100 to $300, while cleaning or replacing fuel injectors can cost between $50 and $200. Vacuum leak repairs and engine timing adjustments may incur additional costs. Overall, the total repair cost for this issue can range from $200 to $800, including parts and labor. It's recommended to consult with a trusted mechanic to get an accurate estimate based on your specific vehicle and location.

Tech Notes for P0303 2003 Infiniti G35

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.

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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 2003 Infiniti G35 Code

1. What does the OBDII code P0303 mean on a 2003 Infiniti G35?

P0303 indicates a misfire has been detected in cylinder number 3 of your engine.

2. What are the symptoms of a P0303 code in a 2003 Infiniti G35?

Common symptoms include rough idling, engine hesitation, reduced fuel efficiency, loss of power, and the Check Engine Light illuminating.

3. What causes a P0303 code on a 2003 Infiniti G35?

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

4. Can driving with a P0303 code damage my 2003 Infiniti G35?

Yes, prolonged driving with a misfire can damage the catalytic converter and other engine components, so it’s best to address the issue promptly.

5. How do I diagnose a P0303 code on my Infiniti G35?

Start by inspecting the spark plug and ignition coil in cylinder 3. Then, check the fuel injector, vacuum hoses, and perform a compression test if needed.

6. How do I fix a P0303 code on a 2003 Infiniti G35?

Repairs may involve replacing the faulty spark plug, ignition coil, or fuel injector, addressing vacuum leaks, or repairing engine mechanical issues.

7. Can a dirty fuel injector cause P0303 in a 2003 Infiniti G35?

Yes, a clogged or malfunctioning fuel injector can lead to a misfire in cylinder 3, triggering the P0303 code.

8. How much does it cost to fix a P0303 code on an Infiniti G35?

Costs vary depending on the cause, but replacing a spark plug or ignition coil typically costs $100–$300, while more extensive repairs like addressing compression issues can be more expensive.

9. Can bad fuel cause a P0303 code in a 2003 Infiniti G35?

Bad or contaminated fuel can contribute to misfires, so using high-quality fuel is important to prevent such issues.

10. How can I prevent a P0303 code from recurring on my Infiniti G35?

Regular maintenance, including timely spark plug replacements, fuel injector cleaning, and checking for vacuum leaks, can help prevent cylinder misfires.

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