Same here 2021 Tahoe 5.3l, 130 miles on it.Wife first drive and starts it up —engine rocks and roll all over the place and then dies in driveway. Merry Xmas . #4 valve spring is busted. Dealer swears all is fine. Wife does not want it-“no longer a new car”....the fixed vehicle sits at dealer. Just pulled my vacation for holidays. Safer at work.