I know it is different state to state but I just filed for lemon law through a company that specializes it. My truck has a loud cold start knock. See the video. listen to it all the way.
I had a phone consultation and since they claim there is no fix available, per CT lemon laws, I have a good case. I went to go and price a Tundra and had them look at my Silverado as a trade. They straight up told me they want nothing to do with the truck due to the engine knocking. This knock just like any other serious noise kills the value of a new truck due to no one wanting to buy it. At this point I cant even get rid of it because no one wants it.
Gm's customer service was a joke. I was bounced around between advisors and would be promised call backs that I never got. I found my advisors direct extension and she started screening my calls. She wouldn't answer when I call on my cell(number they have on file). I call right after from my work phone and she picked right up. Over the last 3 months I spent over 6 hours of waiting on hold to talk to someone. Finally They told me 2 weeks ago to bring the truck in for further diag. I call the dealer and they tell me GM hasn't okayed anything yet. I call GM for 100th time and after 2 week of them trying to figure out what to do they tell me again no fix and they cant do anything for me. No concern, no care, nothing. Based on how I was treated I want nothing to do with this junk vehicle. I even asked to talk to the manager of the department and EVERYTIME I asked they were in meetings and don't take calls. How they handle this was truly embarrassing. That it was prompted me to trade the truck in, but then come to find out no one wants it.