I just pulled out my plugs at 120K and found oil all the way up to the tip on #6 plug, went right to the PCV and found it stuck. Cleaned the PVC did not replace valve covers, no leak now. Why did'nt infinity know this, defective design on the PCV it's too small on the center hole. They say plugs good to 100K, so if U did'nt check it warranty expires and were screwed!!! PCV root cause check it often.