Ok so long story short. I'm lost the dealership is lost so here it is. This is a random occurrence. Drive vehicle runs like a top, park turn off no issues. Go eat come back try to start, and that's where it goes bad. Get shift to park message, service stabilitrak, service 4 when drive and it will not start. Turn off power driving lights stay on light on push button on few minutes later everything turns back on with same messages with check engine light on. Only way to get it to start is get shifter into neutral. Once it starts downshifts like crap until you reset the TCM . Once you go thru that drives great no messages and check engine light goes away. Been at deal for 3 days they have no clue.