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Engine-Codes – Mitsubishi – P0303 Mitsubishi

P0303 Mitsubishi Code - Cylinder 3 Misfire Condition

Quick Answer

The P0303 diagnostic trouble code (DTC) for Mitsubishi vehicles indicates a misfire in cylinder 3. Common causes include Faulty spark plug in cylinder 3, Failing ignition coil specific to cylinder 3, Clogged fuel injector for cylinder 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 Mitsubishi indicates Cylinder 3 Misfire Condition.
Common causes
Common causes include Faulty spark plug in cylinder 3, Failing ignition coil specific to cylinder 3, Clogged fuel injector for cylinder 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.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0303 Mitsubishi Description

The P0303 diagnostic trouble code (DTC) for Mitsubishi vehicles indicates a misfire in cylinder 3. This means that the engine's computer has detected that cylinder 3 is not firing properly, leading to a lack of power, rough idle, and potentially increased emissions. A misfire can be caused by a variety of issues, such as spark plug or ignition coil problems, fuel delivery issues, or mechanical problems within the engine.

OBDII Code P0303 Mitsubishi - Cylinder 3 Misfire Condition
P0303 Mitsubishi Code - Cylinder 3 Misfire Condition

Common Causes of P0303 Mitsubishi

  1. Faulty spark plug in cylinder 3.
  2. Failing ignition coil specific to cylinder 3.
  3. Clogged fuel injector for cylinder 3.
  4. Vacuum leaks affecting cylinder 3.
  5. Low compression in cylinder 3.

Symptoms of P0303 Mitsubishi

  1. Rough idle or shaking sensation while driving.
  2. Loss of power or acceleration.
  3. Engine misfires or stutters during acceleration.
  4. Increased fuel consumption.
  5. Illuminated check engine light.

How to Fix P0303 Mitsubishi

  1. Diagnose the specific cause of the misfire by using a scanner to pinpoint cylinder 3.
  2. Replace the spark plug in cylinder 3 if found to be faulty.
  3. Test and replace the ignition coil for cylinder 3 if necessary.
  4. Clean or replace the fuel injector for cylinder 3.
  5. Check for vacuum leaks and repair as needed.

Cost to Fix P0303 Mitsubishi

The cost of repairing a cylinder 3 misfire can vary depending on the underlying cause of the issue. Typically, replacing a spark plug can cost between $50-$150, while an ignition coil replacement may range from $100-$300. Fuel injector cleaning or replacement could cost $50-$200, and diagnosing the issue may involve an hour or more of labor charges. Overall, the total cost of resolving a P0303 code could range from $200-$600, including parts and labor. It's recommended to consult with a qualified mechanic to get an accurate estimate based on your specific vehicle and location.

What does this mean?

Tech Notes for P0303 Mitsubishi

The P0303 code means that the 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 needs to be done to diagnose problem, see "Possible Causes"

When is the Code Detected?

Engine Cylinder 3 is Misfiring.

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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 Mitsubishi Code

1. What are the common symptoms of a P0303 OBDII code in a Mitsubishi related to Cylinder 3 misfire condition?

- Common symptoms include rough idling, loss of power, engine vibration, and potential stalling.

2. What are some possible causes of a P0303 OBDII code in a Mitsubishi?

- Causes may include a faulty spark plug, ignition coil, fuel injector, vacuum leak, or low compression in Cylinder 3.

3. How can I diagnose a P0303 OBDII code in a Mitsubishi?

- Diagnosis involves checking the spark plug, ignition coil, fuel injector, compression levels, and for any vacuum leaks specific to Cylinder 3.

4. What are some repair tips for fixing a P0303 OBDII code in a Mitsubishi?

- Repair tips may include replacing the spark plug, ignition coil, or fuel injector for Cylinder 3, addressing any vacuum leaks, and performing a compression test.

5. Can driving with a P0303 OBDII code in a Mitsubishi cause further damage?

- Continuing to drive with a misfire can potentially damage the catalytic converter and other engine components over time.

6. How important is it to address a P0303 OBDII code in a Mitsubishi promptly?

- Promptly addressing the code is crucial to prevent further damage to the engine and ensure optimal performance and fuel efficiency.

7. Are there any preventive measures to avoid a P0303 OBDII code in a Mitsubishi?

- Regular maintenance, such as changing spark plugs, inspecting ignition components, and ensuring proper engine performance, can help prevent misfire codes.

8. Can weather or environmental conditions trigger a P0303 OBDII code in a Mitsubishi?

- Extreme weather conditions, such as excessive humidity or temperature, can sometimes contribute to misfire conditions, but underlying issues should still be addressed.

9. How much does it typically cost to repair a P0303 OBDII code in a Mitsubishi?

- Repair costs can vary depending on the specific cause of the misfire, but expenses may include parts and labor for component replacements or repairs.

10. Can a P0303 OBDII code in a Mitsubishi be reset without fixing the underlying issue?

- While the code can be cleared temporarily, it is essential to address the root cause of the misfire to prevent the code from recurring.

Discuss the causes and fixes for P0303 Mitsubishi OBDII Code

Submit a New Comment

  • Alright so I replaced all my spark plugs and spark plug wires last year and replaced all my ignition coils last night and still the light is on and missing help

    Reply to Comment

  • If you have new spark plugs and coil, then you probably have a faulty fuel injector. What model and year is your Mitsubishi?

    Reply to Comment

  • I had a cylinder 3 misfire code this last winter. I replaced all six coils and plugs, head cover gaskets, PCV valve etc. I resealed the intake manifold and throttle body. I cleaned the throttle body prior to reassembly and I put a can of SeaFoam in the tank every third fillup. Yesterday, less than 6 months after that I threw up another Cylinder 3 misfire. Any thoughts?

    Reply to Comment

  • Is the engine misfiring as well or is just the code? any excessive smog?

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  • The engine does misfire but no smog. It also knocks excessively.

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  • The next step is to perform a compression test. You may have a bent valve or piston ros

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  • All cylinders test at least 175 psi. The # 3 cylinder tested at 180 and 185 psi.

    Reply to Comment