cause its turbo???? hahaha jkz jkz

U could have a vacuum leak on some where, double check all ur vac lines, zip tie em if u have to... Leaks are hard to find by sound an eye sight

Could also be that ur TB gasket has gone, could b wrong but... ANd also check ur line, the breather hose that runs from the rocker cover to the Intake arm isnt loose or crack, again which can result in the sound