Congrats on 30 years no…
Congrats on 30 years no problems with Toyota. I've worked for every major manufacturer at dozens of Chicago area dealerships since 1995 and have seen the craziest things with vehicles and more now than ever with all the ridiculous tech in these vehicles- like a Jeep that refused to keep it's menus in English. Anyhow my suggestion is certainly try another store. So often what can't be sorted by one shop is figured out easily by another. While they all have access to the same info from GM it's just like going to a Dr. They all have different experience and thought processes that can aide in correcting this. Take one last shot trying a new dealer service shop while preparing to utilize lemon law, that's why it's there. It'll take some time and more frustration but ultimately you're never going to be happy with this truck even if they fix it you'll always have this entire experience in your toolbox of feelings. Move on. And it may be just this one Silverado that sucks - i currently work for a Chevy dealer and haven't heard this as a common event. Every mass production item have a few that make it into the world . I hope u resolve this and get one u r happy with