P0304 Fault Code

Cylinder 4 Misfire Detected

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0304 code indicates that the engine control module (ECM) has detected a misfire in cylinder 4. Engine misfires can lead to increased emissions, poor fuel economy, and potential engine damage if not addressed promptly. Understanding the underlying issues can help in diagnosing and resolving the problem effectively.

What are the symptoms of the P0304 code?

• Rough engine idle or operation
• Decreased fuel efficiency
• Illuminated check engine light (CEL)
• Excessive exhaust emissions
• Engine stalling or hesitation during acceleration

What causes the P0304 code?

• Defective spark plug or ignition coil in cylinder 4
• Fuel delivery issues, such as clogged fuel injectors
• Vacuum leaks affecting the air-fuel mixture
• Low compression in cylinder 4 due to mechanical issues
• Faulty engine control module (ECM)

How to fix P0304?

• Inspect and replace the spark plug in cylinder 4 if worn or damaged
• Test and replace the ignition coil if faulty
• Clean or replace fuel injectors as necessary
• Check for vacuum leaks and repair them
• Conduct a compression test and address any mechanical issues in cylinder 4
• If all else fails, test the ECM and replace if defective