P0304 Audi Code – Causes, Fix & Cost

Detailed Overview

The P0304 code indicates a misfire in cylinder 4. Common causes include a faulty ignition coil, worn spark plug, or fuel injector issues. Audi engines are sensitive to ignition performance, so even minor faults can trigger this code.

Step-by-Step Diagnosis

🔧 Scan and confirm P0304 code
🔧 Inspect spark plug and ignition coil
🔧 Swap coil with another cylinder
🔧 Check fuel injector
🔧 Perform compression test

Common Mistakes

⚠️ Replacing parts without testing
⚠️ Ignoring ignition coil issues
⚠️ Skipping injector checks

Cost Breakdown

DIY: $50 – $200
Independent Shop: $200 – $600
Dealership: $400 – $1000

Frequently Asked Questions

Can I drive with P0304?

Not recommended, as it can damage the catalytic converter.

What causes P0304?

Ignition coil failure, worn spark plugs, or injector issues.

How much does it cost to fix P0304?

$150–$800 depending on repair.

Related Codes

P0300 P0301 P0302 P0303

P0304