Cylinder 4 Misfire Detected - Causes & Fixes
Learn what P0304 means, why cylinder 4 is misfiring, and how to fix it. Complete guide with symptoms, causes, and step-by-step solutions.
Engine Problems
Symptoms
- 1Check engine light flashing or steady
- 2Rough idle or engine vibration
- 3Lack of power during acceleration
- 4Poor fuel economy
- 5Engine hesitation or stumbling
Common Causes
- 1Worn or fouled spark plug in cylinder 4
- 2Faulty ignition coil on cylinder 4
- 3Damaged spark plug wire or boot
- 4Vacuum leak near cylinder 4
- 5Low fuel pressure or clogged fuel injector
- 6Low compression in cylinder 4
How to Fix
- 1Replace the spark plug in cylinder 4
- 2Test and replace the ignition coil if faulty
- 3Inspect and replace spark plug wires if damaged
- 4Check for vacuum leaks and repair
- 5Test fuel injector and clean or replace
- 6Perform a compression test if other fixes fail
What Does P0304 Mean?
The P0304 code indicates that your vehicle's engine control module (ECM) has detected a misfire in cylinder 4. A misfire occurs when the air-fuel mixture in a cylinder fails to ignite properly, leading to reduced engine performance and potential damage if left unaddressed.Why Is This Code Important?
Cylinder misfires can cause serious problems including:- Increased emissions and failed emissions tests
- Damage to the catalytic converter (expensive repair)
- Poor fuel economy
- Engine damage if ignored long-term
How AI4Car Helps
Our AI-powered diagnostic tool can help you understand the severity of the P0304 code in your specific vehicle, provide personalized recommendations, and track whether the issue returns after repairs.Related Codes
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