Because there are several posts regarding piston slap on a cold start up, I wanted to add my opinion and preference for an oil additive. If you want to make the piston slap less noticeable or improve your engine's performance, go online and order an additive call X1R. I've used it for many years in all my vehicles, and i feel that it outperforms anything else on the market. It works better than Lucas products, ZMax, or any of the other hundreds of products out there. Give it a try, I don't think you'll be disapointed. Hope this helps anyone who is trying to figure out what additive to use.