AudiForums.com - Juddering on acceleration

2011 Audi A3 S-line 2.0 Quattro which has just started intermittently juddering/cutting out when accelerating. It will do it one or two times in quick succession, dropping all power and then return back to accelerating. It's difficult to describe, but it almost feels like a blockage. Only started doing it since it had its emissions 'fix' at Audi. Coincidence or not? Audi certainly think so....snakes. 🐍

Anyone any ideas?
Or can you have the emissions work reversed?