Twincharged
 

https://cimg2.ibsrv.net/gimg/www.hom...8c173dddec.jpg
The ecu is seeing too much boost at low rpm with supercharger causing the ecu to close throttle momentary . This in turn opens dump valve releasing all boost pressure. The car will pogo effect like this until rpms increase - then turbo spools in and all normal again. Something to do with map sensor I suspect - what do I need to do without mapping ?