My 2002 Yukon XL has thee worst cold piston slap of any 5.3 I've ever heard. And I've owned and drove many. Random citizens with likely no car knowledge whatsoever turn and stare when I fire it up and drive off. I'm sure the neighbors are confused because my driveway looks like James Bond lives here but half the time I'm rolling out in something that sounds like it's about to blow up. It has the charm of a rod knock but it is merely piston slap. Piston slap so bad it throws the knock sensors off for the first 30 seconds if it's below freezing. I bought it in the summer so I didn't get fully acquainted with the severity until this winter. I changed the clean Jiffy Lube oil when I bought it and put in MaxLife 10w30. It hardly has burned a drop of oil in 5000 miles, burns rubber though. I'll probably change it at 7k. No complaints for a $1500 beater that was maintained and had newer tires, brakes, and cooling system. Anyone want to throw a guess on if wear metals will be higher with this condition? I can't see how it wouldn't. I mean, something is smashing into something every time I cold start it. You can still lightly hear it when it's fully warmed up.