The P0302 diagnostic code on your 2020 Nissan Maxima indicates that cylinder 2 is experiencing misfires detected by the engine control module. The eighth-generation Maxima features the 3.5L VQ35DE V6 engine producing 300 horsepower. This port-injection variant of Nissan's VQ V6 has well-documented diagnostic characteristics.
VQ35DE Engine Overview
The 3.5L VQ35DE is a 60-degree V6 with dual overhead cams and port fuel injection. Cylinder 2 is located on the rear bank (firewall side). Unlike direct-injection variants, the VQ35DE uses traditional multi-port injection where fuel sprays onto intake valves, reducing carbon buildup concerns. The engine includes continuously variable valve timing for optimal performance.
Common Causes of Misfire
Ignition coil failure is common on VQ35DE engines, particularly with age and heat exposure. Spark plug degradation reduces ignition energy over time. Fuel injector clogging affects cylinder 2 fuel delivery. Vacuum leaks near the intake manifold can cause lean conditions. Timing chain stretch on higher-mileage examples can affect valve timing accuracy.
Symptom Recognition
The smooth VQ V6 becomes noticeably rough when cylinder 2 misfires. Idle quality deteriorates with noticeable vibration. Hesitation during acceleration and reduced power are common. The check engine light illuminates, with severe misfires causing a flashing warning.
Diagnostic Methodology
Scan for all codes and capture freeze frame data. Access cylinder 2 on the rear bank for spark plug and coil inspection. Test ignition coil using swap method or dedicated tester. Check fuel injector operation with noid light and balance test. Verify no vacuum leaks exist. Compression testing confirms mechanical integrity. Higher-mileage vehicles may warrant timing chain inspection.
Effective Repairs
Replace spark plugs with NGK or Denso iridium units. Replace faulty ignition coils. Clean or replace fuel injectors showing poor flow. Repair vacuum leaks using proper gaskets and sealants. Address timing chain stretch if diagnosed on higher-mileage vehicles.