P0304 — Cylinder 4 Misfire Detected
Category: Powertrain Severity: High
Updated:
DTC code P0304 means: Cylinder 4 Misfire Detected. It falls under the "Powertrain" category, with an estimated severity of High. Common causes include faulty spark plug or coil (cylinder 4), faulty fuel injector (cylinder 4) and vacuum leak; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Faulty spark plug or coil (cylinder 4)
- Faulty fuel injector (cylinder 4)
- Vacuum leak
- Low compression (cylinder 4)
Symptoms
- Engine vibration
- Loss of power
- Higher fuel consumption
- Engine may not start
How to diagnose it step by step
- Swap the cylinder 4 coil.
- If the misfire follows it, replace it.
- If not, swap the spark plug.
- Check the injector and compression if it persists.
How to fix it
Check spark plugs, coils and position sensors (crankshaft/camshaft); replace any faulty part.
Estimated repair cost
$10–400 depending on the part.
Frequently asked questions
What does DTC code P0304 mean?
Cylinder 4 Misfire Detected.
Is code P0304 serious?
Severity High. Have it checked as soon as possible, especially if it affects safety or the catalytic converter.
Can I keep driving with code P0304?
Avoid it if the light is flashing; with a steady light, only as needed.
Related codes
P0303 P0305 P0302 P0306 P0301 P0307 P0300 P0308 P0316 P0320
Refine by car make
- Audi P0304: Cylinder 4 individual coil pack.
- BMW P0304: Cylinder 4 coil/spark plug.
- Citroën P0304: Spark plugs, coils, or position sensor.
- Dacia P0304: Spark plugs or coils.
- Fiat P0304: Spark plugs or coils.
- Ford P0304: Cylinder 4 coil or spark plug.
- Honda P0304: Spark plugs, coils, or position sensor.
- Hyundai P0304: Coils or spark plugs.
- Kia P0304: Coils or spark plugs.
- Mazda P0304: Coils or spark plugs.
- Mercedes-Benz P0304: Spark plugs, coils, or position sensor.
- Nissan P0304: Coils, spark plugs, or position sensor.
- Opel P0304: Cylinder 4 coil or spark plug.
- Peugeot P0304: Cylinder 4 spark plug, coil, or injector.
- Renault P0304: Cylinder 4 spark plug, coil, or injector.
- Toyota P0304: Cylinder 4 spark plug, coil, or injector.
- Volkswagen P0304: Cylinder 4 individual coil pack.
- Volvo P0304: Coils or spark plugs.
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