The 2023 Mazda CX-9 represents the final production year of this three-row SUV, featuring the refined Skyactiv-G 2.5 Turbo engine. When a P0304 code appears indicating a cylinder 4 misfire, addressing it promptly maintains the smooth power delivery and fuel efficiency this family hauler provides.
Understanding P0304 in Your CX-9
The Skyactiv-G 2.5 Turbo engine delivers strong performance through its combination of high compression and forced induction. Cylinder 4 sits at the rear of the inline-4 engine, nearest the firewall. The powertrain control module monitors combustion events through crankshaft position sensor data to detect misfires with precision.
Turbo Engine Factors
The turbocharged Skyactiv engine operates under higher combustion pressures than naturally aspirated versions. This accelerates spark plug wear and demands premium ignition system performance. Direct injection technology, while providing excellent efficiency, can contribute to carbon accumulation on intake valves over extended mileage.
Diagnostic Steps
Locate the cylinder 4 ignition coil at the engine's rear. Inspect for boost system leaks that could cause lean misfires. Remove the spark plug and check electrode condition—turbo engines require plugs in excellent condition. Verify fuel system pressure and injector performance.
Resolution Strategy
Install spark plugs designed for turbocharged operation with proper heat range. Test ignition coil output to ensure adequate spark energy. Check for technical service bulletins that may address drivability concerns. If carbon deposits are suspected, intake valve inspection and cleaning may be necessary.