Got in and service writer supplied info that what I was hearing was common and nothing to be alarmed about. Was surprised that he tried to sell me a package of maintenance items including a fuel induction cleaning. This procedure is not recommended by the manual or apparently GM. I have owned 8 or so new chev vehicles and this has never been recommended before and seems to be a profit motive for the dealership. Leads me to question how much I can trust the dealer.