Nissan 350Z oil in spark plug hole causing misfire in cylinder #4 on Nissan 350Z

Some Nissan 350Z owners report experiencing engine misfires and rough idling due to oil entering the spark plug hole, particularly in cylinder #4. This issue can disrupt the spark plug's ability to ignite the air-fuel mixture, leading to decreased engine performance. The oil leakage may be caused by a faulty valve cover gasket or other factors, such as an intake manifold leak or an air leak around the injector #4 O-ring. Owners have noted that identifying these leaks can be done by spraying carb cleaner in the affected areas. Additionally, misfires in cylinder #4 may also stem from faulty spark plugs, vacuum leaks, or fuel injector problems. It is crucial for owners facing these issues to address the root cause promptly to maintain optimal engine performance and prevent further complications.