Have you brought this to the attention of your local dealer? There are many benefits to taking a vehicle to your local dealership. You can guarantee that technicians are certified and that the parts come with a GM parts warranty. For these reasons, I would recommend taking the vehicle to your local dealership to be diagnosed. They should be able to assist you further and have a plan for addressing the issue. I can also look into this issue further. In order to do more research, I will need some more specific information from you such as your name, address, phone number, the VIN for the vehicle, and current mileage. If you have further questions, please feel free to contact me either on the thread or via private message. Thank you.
Tricia, GM Customer Service.