Issues with jolting and shutting off
have a 2013 Acadia SLT1, a few days ago I noticed after backing out of my driveway and putting it into drive there was a delay before it engaged into drive, it only happened the one time. A few days ago as I was driving I noticed that it shifts really smooth to first and when it shifts the 2nd time it feels rough, when I came to a stop light my car jolted and I thought maybe I had been rear ended, and my car shut off. It has been doing this every day for the past 4 days. I've been to a mechanic who could not find a problem and suggested that I take it to the dealer and have it reflashed because that was the only code he got. I had that done today and it did not fix the problem. The dealer can't find an issue either, I am just checking to see if anyone else has had this issue and has found a fix, any help would be greatly appreciated!