Unround engine run after cold start with dropouts and exits

Hello, my V70 III D3 (110 kW/150hp) with Geartronic and Start/Stop from 2017 drives me crazy. Since the purchase in February, I have a phenomenon that he starts to jerk and shake shortly after the perfect start, and then usually to go out. If I start him again, he runs like a Swiss movement, and then to “cough” a few times more noticeably at the next 500 – 1000 m. I changed the pressure sensor on the particle filter, the AGR cooler and the AGR valve. He also has a brand new starter battery. The official Volvo workshop is stunned, the tester does not emit any error message and nothing is displayed in the on-board computer. Fuel consumption is normal, i.e. around 6l/100 km and I hardly drive short distances, because of which he might be able to coke. After swapping the AGR valve and the cooler four weeks ago, the problem had not occurred during the entire holiday in the pre-alpines, on the day of arrival back in d he home and after a total of 2,000 km of distance in the 14 holiday days the phenomenon was immediately back. Does anyone still have a ignite idea here? Thank you already for the help