I have a 2014 with 52k miles and decided to change my plugs because mileage has dropped off the past year and there's a gas smell from the exhaust when I first start it. One plug in the front had oil on the insulator like the o-ring is leaking but 2 in the back had oil on the threads and all plugs looked like they had 100k miles, threads were black on all. There was also some oil around the ports when I took off the plenum. Any one else experienced this? Its running better now and no gas smell. I'm going to order a new PVC valve.