I'm experiencing some issues with my Infiniti's engine and I wanted to see if others have had similar problems. The symptoms started with a rough idle and low power output, but things took a turn for the worse when I noticed oil leaks around the valve cover gasket. Research suggests this could be related to faulty PCV (positive crankcase ventilation) systems or even more serious issues like cracked engine blocks. Has anyone else encountered similar problems? Are there any telltale signs that indicate engine trouble?