NHTSA Complaint #11099534 — 2017 GMC ACADIA

I WENT TO A LOCAL DEALER AND COMPLAINED ABOUT A VIBRATION/RUMBLE WHILE DRIVING. IT HAPPENED MOSTLY AROUND 1200-1700 RPM. THE SERVICE MANAGER HEARD OF THE PROBLEM. THERE WAS A MANUFACTURERS BULLETIN OUTLINING THE PROBLEM AND SUGGESTING A FUEL MANAGEMENT SOFTWARE UPGRADE. THIS WAS DONE. THE BULLETIN ALSO APPLIED TO CADILLAC XT5, WHICH IS ON A SHARED PLATFORM WITH MY 2107 GMC ACADIA DENALI AWD. THERE ARE NOW SEVERAL NEW RPM RANGES WHEN THE VIBRATION/RUMBLE OCCURS IN ADDITION TO THE OLD 1200-1700. NOT ONLY HAS THE OLD PROBLEM RE-APPEARED BUT THERE ARE CERTAIN CONDITIONS ABOUT 1500 RPM WHEN I AM STARTING OUT FROM A STOP FOR ABOUT 50 FEET WHERE THE PROBLEM SEEMS TO ALMOST STALL OUT AND THEN WITH A BIG CLANK (LIKE DOWN SHIFTING OR TRANSMISSION IS SLIPPING AND THEN SUDDENLY ENGAGES) AND TAKES OFF. I CANNOT HELP BUT THINK THERE IS GOING TO BE A MECHANICAL BREAKDOWN OF SOMETHING DUE TO THE SUDDEN ENGAGEMENT AND CLANK OR EVEN STALLING OUT IN TRAFFIC, IF THIS PROBLEM IS NOT FIXED. I CONTACTED THE DEALER ONCE AGAIN BUT HAVE NOT HEARD BACK YET.