First I am an Engineer on a towboat, two 3000 hp EMDs, taking readings doing dailies, weeklies, monthlies, looking for leading indicators of potential problems. I am not a car mechanic.

On 6/24/21 first time I drove wife's new Buick Envision on way to church. Less than 5 minutes from house on flat ground accelerating up to 35 MPH speed limit a real hard jerking happened. Immediately I look at tach, no fluctuation. Long story short we have had vehicle back at dealership twice, first time I waited, nothing found on ' codes '. Second time left vehicle 6/28/2021 and more data given to dealership as to when jerking occurs. They acknowledged vehicle doing it, updated ECM and TCM, Engine Control Module and Transmission Control Module.

Picked up vehicle 7/2/2021 left dealership and in less than 1 mile it did it 3 times at 20-40MPH, basically accelerating from stop lights, flat ground. took right back to Buick Dealership. On 7/9/2021 when my wife called Dealership at 0745 they wanted her to ' drive it '. Neither of us could get there that day, picked up on Saturday 7/10/2021. Of course no one other than receptionists were there on Saturday. We got General Manager to take test drive with wife and I and he felt/experienced what we were talking about.

Just got back from dealership, 7/12/2021, talked to tech, they want us to drive 1500 miles so modules can calibrate. Got more printed documentation from them. Told them it is still doing jerking, we are to bring back if it gets worse or by next Monday.