Well I got the knocking sound and then a #6 misfire. Opened up the valve cover to find that my #4 exhaust lifter looks like it came apart inside. Gonna have to pull the head to see how bad things are. Anyone else seen this? These are as good as I could get with the scope I have.
I haven't in personally experienced it yet but I did see it at the dealership once and have heard of it several times. My guess is this is a newer direct injection engine. It doesn't happen that often but when it does it typically bends the pushrod as well as damaging the lifter. I often tell people if they have a bent to pushrod to make sure that they check the top of the lifter to make sure it's still intact. It can be caused from a couple different things, one could be the pushrod interfering (newer 2014+) and I sell a replacement for that on my website. The other option is that the VLOM is leaking and partially activating the lifter causing it to fail thus causing the pushrod to hammer against it unevenly which eventually damages it. When that happens it's best to install the VLOM plug and a disable AFM in the tune