The P0304 code in your 2024 Subaru WRX indicates the powertrain control module has detected persistent misfires in cylinder 4. The performance sedan's 2.4L turbocharged boxer demands understanding of both forced induction and the sport-tuned application for effective diagnosis.
Understanding P0304 in the 2024 WRX
The 2024 WRX continues with the 2.4L FA24 turbocharged boxer producing 271 horsepower. Subaru's horizontally-opposed configuration positions cylinder 4 at the rear of the left (driver's) bank. The performance-oriented application demands precise combustion across all cylinders for optimal power delivery.
Performance Application Considerations
The WRX's sport-tuned turbo operates under demanding conditions compared to standard Subaru applications. High boost pressures and enthusiastic driving stress ignition components. Spark plugs must reliably fire under elevated cylinder pressures. Performance driving accelerates normal wear patterns beyond typical schedules.
Diagnostic Process
Retrieve all codes including any boost or performance-related faults. Analyze freeze frame data noting driving conditions when misfires occurred. Locate cylinder 4 on the left bank rear position. Test ignition coil output against performance specifications. Inspect spark plug condition. Verify fuel injector operation.
Repair Implementation
Install Subaru-approved spark plugs designed for the FA24 turbo application. Clean spark plug wells before removal. Replace ignition coils testing outside specifications. Consider shortened maintenance intervals for track or spirited street use.