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P0304 2002 Nissan Sentra Code - Number 4 Cylinder Misfire Detected

Quick Answer

The diagnostic trouble code (DTC) P0304 for a 2002 Nissan Sentra indicates that there is a misfire detected in the number 4 cylinder of the engine. Common causes include Worn or fouled spark plugs in the number 4 cylinder, Faulty ignition coil specific to the number 4 cylinder, Clogged or malfunctioning fuel injector in the number 4 cylinder. 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
P0304 2002 Nissan Sentra indicates Number 4 Cylinder Misfire Detected.
Common causes
Common causes include Worn or fouled spark plugs in the number 4 cylinder, Faulty ignition coil specific to the number 4 cylinder, Clogged or malfunctioning fuel injector in the number 4 cylinder.
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 Sep 12, 2024
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Code P0304 2002 Nissan Sentra Description

The diagnostic trouble code (DTC) P0304 for a 2002 Nissan Sentra indicates that there is a misfire detected in the number 4 cylinder of the engine. This means that the cylinder is not firing properly, which can lead to a variety of issues with the vehicle's performance. The engine control module (ECM) monitors the firing of each cylinder based on signals received from the crankshaft position sensor and camshaft position sensor. When a misfire is detected, it can result in poor fuel economy, rough idling, decreased power, and even potential damage to the catalytic converter over time.

OBDII Code P0304 2002 Nissan Sentra - Number 4 Cylinder Misfire Detected
P0304 2002 Nissan Sentra Code - Number 4 Cylinder Misfire Detected

Common Causes of P0304 2002 Nissan Sentra

  1. Worn or fouled spark plugs in the number 4 cylinder.
  2. Faulty ignition coil specific to the number 4 cylinder.
  3. Clogged or malfunctioning fuel injector in the number 4 cylinder.
  4. Vacuum leak affecting the number 4 cylinder.
  5. Low compression in the number 4 cylinder due to issues like worn piston rings or a damaged cylinder head gasket.

Symptoms of P0304 2002 Nissan Sentra

  1. Rough idling or vibrations while the engine is running.
  2. Decreased acceleration and overall power.
  3. Increased fuel consumption.
  4. Engine may hesitate or stumble during acceleration.
  5. Check Engine Light illuminated on the dashboard.

How to Fix P0304 2002 Nissan Sentra

  1. Diagnose the specific cause of the misfire by conducting a thorough inspection of the ignition system, fuel system, and engine compression.
  2. Replace the spark plugs in the number 4 cylinder if they are worn or fouled.
  3. Test and potentially replace the ignition coil for the number 4 cylinder if it is faulty.
  4. Clean or replace the fuel injector for the number 4 cylinder if it is clogged or malfunctioning.
  5. Perform a compression test on the number 4 cylinder to check for any internal engine issues causing low compression.

Cost to Fix P0304 2002 Nissan Sentra

The cost of repairing a number 4 cylinder misfire in a 2002 Nissan Sentra can vary depending on the specific cause of the issue. Generally, replacing spark plugs and ignition coils can range from $100 to $300, while cleaning or replacing fuel injectors may cost $50 to $150. If there are more serious internal engine issues causing the misfire, the repair costs could increase significantly. It is recommended to consult with a trusted mechanic to get an accurate estimate based on the specific diagnosis and necessary repairs.

What does this mean?

Tech Notes for P0304 2002 Nissan Sentra

The P0304 code means that cylinder #4 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 #4. 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 P0304 2002 Nissan Sentra Code

1. What does the OBDII code P0304 mean for a 2002 Nissan Sentra?

P0304 indicates that the engine control module (ECM) has detected a misfire in cylinder number 4.

2. What are the common symptoms of code P0304 in a 2002 Nissan Sentra?

Symptoms include rough idling, reduced engine performance, poor fuel economy, engine hesitation, and possibly the check engine light illuminating.

3. What causes a P0304 code in a 2002 Nissan Sentra?

Common causes include faulty spark plugs, a bad ignition coil, a clogged fuel injector, low cylinder compression, or vacuum leaks near cylinder 4.

4. Can driving with a P0304 code damage my engine?

Yes, prolonged driving with a misfire can damage the catalytic converter or other engine components over time.

5. How do I fix a P0304 code on my 2002 Nissan Sentra?

Repairs may involve replacing the spark plugs, ignition coil, or fuel injector for cylinder 4, or addressing underlying issues like vacuum leaks or low compression.

6. How can I determine if the spark plug is causing the P0304 code?

Inspect the spark plug for wear, fouling, or damage. Replacing it with a new one is a simple and cost-effective first step.

7. How do I check if the ignition coil is the problem for P0304?

Swap the ignition coil from cylinder 4 with another cylinder. If the misfire moves to the swapped cylinder, the coil is faulty.

8. Can a dirty fuel injector cause the P0304 code?

Yes, a clogged or malfunctioning fuel injector can prevent proper fuel delivery to cylinder 4, leading to a misfire.

9. What should I do if I’ve replaced the spark plug and coil but still get a P0304 code?

Check for vacuum leaks, perform a compression test on cylinder 4, and inspect the fuel injector for proper operation.

10. Is it expensive to fix a P0304 code in a 2002 Nissan Sentra?

Costs vary depending on the cause. Replacing a spark plug or ignition coil is relatively inexpensive, while addressing low compression or injector issues may be more costly.

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