I am leaning toward a bad lifter..... but, not sure that would restrict oil flow to the rocker.... Could measure how far the rocker moves, and then compare that to another one.... See how much difference there is.

 

I’ll have to get a dial indicator and see

 

These are not supposed to be under the valve cover! They are to keep the wire harnesses in place. They are taped to the harness and after the valve cover is on they go on the stud to keep them in place.

 

I was also going to mention, those look like the engine harness holder clips that go on the valve cover studs

 

That makes a lot more sense. They must’ve fell in when I resealed the valve covers a couple thousand miles ago, the same time I did the plenum plate. It still had a rattle from the valve cover before I did the reseal, and also still had a misfire before.

 

Those can be a huge PITA to pry off their respective studs. Honestly, be glad they're gone.....but be less glad if they were living inside the vc