DTC P0304 — Cylinder 4 Misfire Detected
P0304 indicates: Cylinder 4 Misfire Detected.
Diagnostic summary
P0304
What it means
Cylinder 4 Misfire Detected
Can you drive?
🛑 Do not drive
Urgency
High 7/10
Typical price
$50 – $600
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Updated Jul 9, 2026 Seen on Powertrain
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ℹ️ What does it mean?
Cylinder 4 Misfire Detected
🔍 Symptoms
- • Check Engine Light on
- • Reduced engine performance
- • Increased fuel consumption
- • Unusual engine behavior
⚠️ Possible Causes
- ⚠ Worn spark plug
- ⚠ Faulty coil pack
- ⚠ Bad injector
- ⚠ Low compression
🚗 Can I drive with this code?
Do not drive
Not safe to continue driving. Repair immediately.
🔧 How to Diagnose
- 1 Read DTCs with OBD-II scanner
- 2 Check freeze frame data
- 3 Inspect related components
- 4 Clear codes and test drive
🛠️ How to Fix
- 1 Replace spark plug
- 2 Replace ignition coil
- 3 Test injector
- 4 Check compression
💰 Estimated Repair Cost
Repair cost by car / region
Early rough estimate. Accuracy improves as more real repair stories are added.
DIY / parts$18 – $390
Mechanic / labor$23 – $450
Repair range$50 – $600
❓ FAQ
What does P0304 mean?
Cylinder 4 Misfire Detected
How serious is P0304?
Severity: high. Not safe to continue driving. Repair immediately.
How much does it cost to fix P0304?
Estimated repair cost: $50–$600 depending on vehicle and region.
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