I have a 2012 Jeep wrangler unlimited with 20k miles the check engine light came on two days ago and I took it to autozone to see what was wrong, they said it was misfireing on the #6 cyl. I checked the plugs, none were bad so I called the dealer and ask about the problem, they told me the 3.6L engine was having so problems with the valves sticking. Has anyone else had this problem with their Jeeps?