The P0304 code in your 2020 Nissan Maxima indicates the engine control module has detected persistent misfires in cylinder 4. Nissan's flagship sedan features a high-output 3.5L V6 that demands precision diagnosis to restore the smooth power delivery expected from this performance-oriented vehicle.
Understanding P0304 in the 2020 Maxima
The 2020 Maxima features the 3.5L VQ-series V6 producing 300 horsepower through variable valve timing and direct fuel injection. This transverse-mounted V6 positions cylinder 4 on the rear bank, closest to the firewall. The engine management system identifies cylinder 4 misfires through crankshaft velocity pattern analysis with high precision.
Performance Sedan Misfire Causes
The high-output V6 demands quality ignition components to maintain its performance character. Spark plug electrode wear affects ignition reliability. Ignition coils face elevated demands from the performance-oriented combustion environment. Direct injection contributes to intake valve carbon accumulation over time. Fuel injector precision directly affects the engine's refined power delivery.
Diagnostic Approach
Retrieve all codes and analyze freeze frame conditions when misfires occurred. Access the rear bank for cylinder 4 inspection—the transverse mounting positions this bank toward the firewall. Test ignition coil output ensuring performance-grade capability. Inspect spark plug condition. Verify fuel injector operation meets precision requirements.
Repair Solutions
Install Nissan-specified spark plugs designed for the high-output V6. Replace ignition coils showing degraded output—performance applications demand reliable ignition. Address fuel system precision through cleaning or component replacement. Carbon cleaning benefits higher-mileage vehicles showing related symptoms.