Just wanted to share a solution I had if you cover that says ecotec and covers the spark plugs rattles too much. I have some of that self fusing silicone tape and wrapped the clips that hold the cover down. It stop rattling. Mine was rattling bad after I got the new manifold and valve/cam cover because my pcv died.
I drove it about two weeks like that before I sold the car and had no problem. So not sure how it would hold up in the long run but I don't see why it wouldn't hold up.
See less