P0304
Cylinder 4 Misfire Detected
Description
Cylinder 4 Misfire Detected. This powertrain diagnostic trouble code covers the engine, the fuel and ignition systems, emission control and the transmission.
OBD Codes Details
Possible Causes
Worn spark plugs, failed ignition coil, faulty injector, low compression in a cylinder
Solution
Read misfire counters per cylinder, inspect plugs and coils, swap the coil and injector to a neighbouring cylinder, run a compression test
Symptoms
- Engine performance issues
- Reduced power or acceleration
- Poor fuel economy
- Engine running rough
Diagnostic Recommendations
- Scan for additional powertrain codes
- Check engine performance parameters
- Inspect fuel and ignition systems
- Test sensors and actuators
Repair Cost Estimate
- Basic diagnostic: $100-200
- Sensor replacement: $100-500
- System repair: $200-1500
- Major engine work: $1000-5000
Was this helpful?
Loading...
Send Feedback
Found an error or have a suggestion? We respond within 48 hours.
Fact-checking completed
Verified by:
Pavel Volkov
Created:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
Learn More
Dive deeper with our comprehensive developer guides for OBD Codes
Related Codes
More codes of the same type