Full disclosure - they only had three 4412's in stock at Autozone so I put in the Champion 3034's which *are* platinum. Could be a Bosch issue although I've like them in my Fords. Also when I pulled them out I could tell they hadn't been torqued to spec but none of them looked bad. I greased the threads and torqued them to 25 ft/lbs - spec is 26-30 ft/lbs. - but it felt like I was there so I stopped. So far no more ping.