How much does it cost to fix P0304?

Typical repair cost is $100–$1,000.

P0304 — Cylinder 4 Misfire

High Severity · Engine

OBD-II code P0304 means your vehicle's ECU detected: Cylinder 4 Misfire. Below: causes, step-by-step fixes, and repair cost — free, no signup needed.

High severity — do not ignore. Get a diagnosis promptly to avoid further engine damage.

Typical Repair Cost

$100–$1,000

Parts + labor, national average

Severity

High

Address as soon as possible

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Common Causes of P0304

Spark plug
Coil pack
Injector
Compression

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How to Fix Code P0304

Replace spark plug #4

Swap coil to diagnose

Test injector

Compression test

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FAQ — Code P0304

What does OBD-II code P0304 mean?

P0304 means your vehicle's onboard computer detected: Cylinder 4 Misfire. This is a high-severity code in the Engine category.

How much does it cost to fix code P0304?

Typical repair cost for P0304 is $100–$1,000 including parts and labor. Costs vary by vehicle make, model, and location. A free scan at AutoZone or O'Reilly is a good first step.

Can I drive my car with code P0304?

Code P0304 is high severity. Avoid long drives until diagnosed — continued driving can cause additional engine damage.

What are the most common causes of P0304?

The most common causes are: Spark plug, Coil pack, Injector, Compression. Always start with the cheapest diagnosis step before replacing parts.

Will code P0304 clear itself?

Code P0304 will clear itself after the underlying issue is fixed and the ECU completes several successful drive cycles. Clearing it without fixing the root cause only masks the problem temporarily.

Is P0304 showing on your car?

Enter your VIN for a free vehicle-specific report — recalls, specs, and market value. No signup required.

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OBD-II code data is based on SAE J2012 standards and general repair industry data. Repair costs are national averages and vary by vehicle, location, and shop. Always consult a qualified mechanic for a diagnosis specific to your vehicle.