A P0303 diagnostic code on your 2022 Infiniti QX80 indicates the engine control module has detected repeated misfires in cylinder 3. The full-size luxury SUV uses Nissan's proven 5.6L V8 engine.
5.6L V8 Engine Layout
The 2022 QX80 uses the VK56VD 5.6L V8 producing 400 horsepower with direct injection and VVEL variable valve timing. Cylinder 3 is located on the driver's side (left) bank of this V8.
Common Causes
- Ignition Coil Failure: Individual coil-on-plug units can fail
- Spark Plug Wear: V8 engines have eight plugs to maintain
- Fuel Injector Problems: Direct injection deposits
- VVEL System Issues: Variable valve timing concerns
- Carbon Buildup: GDI technology leads to valve deposits
Diagnostic Approach
Use a Nissan/Infiniti compatible scanner for detailed V8 diagnostics. Monitor misfire counts across all eight cylinders. Test ignition components through swap testing.
Repair Solutions
Replace failed ignition coils with OEM or quality aftermarket parts. Install Infiniti-specified spark plugs. Address fuel injector issues through cleaning or replacement. Consider carbon cleaning at higher mileages.