Get it on vag-com for a scan first, theres a whole world of possible problems for what you've described.
As an idea, I get the same problem as you which could be cause be a massive boost leak/popped hose, but in my case is down to a pressure drop recorded between the maf and map sensors due to the non recirc. bov as I relocated the bov to cold side and I'm in need a of a hose to recirc. back to intake. Unplugging my maf means the car runs some what better.
So unless you know exactly what's going on with your engine then just get it scanned and go from there.
usually id say change it with another to trial and see if it makes a difference but if thats not possible.. id try blowing into the valve from each exit (there should be 3 some should provide you with resistance.) if you can blow freely through all of the sides then i THINK this is one way of seeing that the valve is faulty..
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