My 2012 G37x sport throws a code P0302 now and then. Runs rough in park for a few days then the light goes off and seems to run fine. Code clears itself. Runs great for a few months and then the light comes on and another P0302 code.
Had spark plugs replaced about 25K ago. Any thoughts on what is going on? I'm dreading taking it to the shop.

 

The issues was the trifecta of solutions. Spark plug tube seal failed. Led to motor oil in the spark plug tube. Will replace valve cover and spark plug and ignition coil. And I get a 27 point inspection!!