Engine-CodesGeneric – P1303

P1303 Code - Cylinder Number 3 Random Misfire Detected

Quick Answer

The diagnostic code P1303 indicates that a random misfire has been detected in cylinder number 3 of the vehicle's engine. Common causes include Faulty spark plug in cylinder number 3, Ignition system issues such as a failed ignition coil or spark plug wire, Fuel delivery problems, such as a clogged fuel injector. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P1303 indicates Cylinder Number 3 Random Misfire Detected.
Common causes
Common causes include Faulty spark plug in cylinder number 3, Ignition system issues such as a failed ignition coil or spark plug wire, Fuel delivery problems, such as a clogged fuel injector.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Table of contents Created and updated by William Orellana on Sep 06, 2024
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Code P1303 Description

The diagnostic code P1303 indicates that a random misfire has been detected in cylinder number 3 of the vehicle's engine. A misfire occurs when the fuel in the combustion chamber fails to ignite at the proper time, leading to a disruption in the engine's smooth operation. This issue can result in poor engine performance, reduced fuel efficiency, increased emissions, and potential damage to the catalytic converter over time if not addressed promptly.

OBDII Code P1303 - Cylinder Number 3 Random Misfire Detected
P1303 Code - Cylinder Number 3 Random Misfire Detected

Common Causes of P1303

  1. Faulty spark plug in cylinder number 3
  2. Ignition system issues such as a failed ignition coil or spark plug wire
  3. Fuel delivery problems, such as a clogged fuel injector
  4. Vacuum leaks in the intake system
  5. Engine mechanical issues, such as low compression in cylinder number 3

Symptoms of P1303

  1. Rough idling or vibrations while the engine is running
  2. Decreased acceleration and power
  3. Engine hesitation or stumbling
  4. Increased fuel consumption
  5. Illumination of the check engine light on the dashboard

How to Fix P1303

  1. Begin by scanning the vehicle's computer to confirm the presence of the P1303 code and identify cylinder number 3.
  2. Inspect and replace the spark plug in cylinder number 3 if it is found to be faulty.
  3. Check the ignition coil and spark plug wire for any signs of damage and replace if necessary.
  4. Test the fuel injector in cylinder number 3 for proper operation or clean/replace if clogged.
  5. Perform a compression test on cylinder number 3 to check for any internal engine issues causing the misfire.

Cost to Fix P1303

The typical repair costs for addressing a cylinder number 3 random misfire detected can range from $100 to $500, depending on the specific cause of the issue and any parts that may need to be replaced. This estimate includes parts and labor, but it's important to keep in mind that actual costs can vary based on the vehicle's make and model, the location of the repair shop, and the extent of the repair needed. It's recommended to consult with a trusted mechanic or auto repair shop for a more accurate cost estimate.

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Code P1303 Information for Specific Makes

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.

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