Originally Posted by sdhberg
I have been having the same problem sporadically with my 2011 2LT for over a year and a half. I have taken it into the dealer several times and they could not find anything wrong. I have had two check engine lights; one for a cylinder misfire and the other was an unknown reason. During a recent long road trip the rattling noise went from sporadic to constant at all times except initial acceleration/deacceleration. Took it back to the dealer and received a call informing me that they talked to GM and will be removing the engine for a teardown/inspection, possible replacement and that GM may be sending an engineer to assist. Hate not having my car for possibly several weeks but am glad this is getting taken care before my warranty expires in 4 months.
Sorry about the extensive process that you're experiencing at the dealership, though I'm happy things are moving forward for you and the vehicle. Feel free to contact me if you need additional assistance regarding communication with the dealership.
Chevrolet Customer Care