[john]

Having the nipple open is letting in unmetered air leading you to fuel cut. Anywhere that air is let into the system after the MAS is unmetered. Therefor your ecu does not see it as airflow and you fuel cut. You do not have to have a boost leak to fuel cut as long as the opening is infront of the turbo (intake pipe). I am hoping that you are not on stock injectors as the turbo will not spool below 17psi. You will have to use your foot on the gas pedal to control the boost. Not a very good idea as far as performance is concerned. Stick the stock actuator on and see if it helps. Plug the nipple for sure though.