Carrier/rack problems of the 2014 GMC Acadia

My Acadia has shut off without warning multiple times. Today, I was in a parking lot picking up a prescription. The car was idling while I was waiting in the pick-up lane and then shut off. The dash remained on and gave the following warnings: traction control off, engine power reduced, service stabilitrack. I tried to restart the engine only to have the car shutter violently while idling. I turned the car off again and then restarted for a second time. This time it restarted as normal and the check engine light came on. I have taken it to a dealer 4 times since October as it has shut off while driving and making a turn. The dealer says there are no codes in the diagnostics and cannot find a problem. I'm terrified to drive the car. I saw a recall from 2014 about an electrical short but I don't know if that was already fixed on this vehicle since I bought it used. I also don't know if this is even related to that recall.

I was driving on the interstate with my son and the rear sun roof exploded. It was a very loud noise and my ear in still hurting from the sound. The sunroof screen was closed, but the glass has not broken apart and fallen yet. It is shattered on the underside in hundreds of pieces. The top shows long cracks all over. There doesn't seem to be a point where something hit it. The crack lines seem random.

We have had the car since January and I guess today was the first day I have driven the car with the back windows down. I took my dog with me so I rolled down the back windows when I did this the whole car started shaking and you could see in the rearview mirror that the back doors shook hard. The shaking made a load racket that hurt me ears. It happened with either back window down but was worst with the driver side. It was real bad with both windows down. I did not get the shaken with the front windows down and the back windows up. It only accured when the back windows were down. It happened at 65 miles an hour and at 40 miles an hour. It has to be a design flaw because it was bad. I first thought it was a bad tire but it went away with windows up and only came back when back windows were down. After making sure the tires were ok, I played with the windows to see when the vibration started and got worst. The vibration would start when either back window would get a fourth of the way down and would get worst as the windows would go down. The faster I went the worst it got. No vibration ever happened when just the front windows were down and no vibration when all windows were up. The car would vibrate enough that it scared me and I think someone needs to look into it and test drive our car thank you.