I'm pretty sure I have a vacuum leak somewhere just want to make sure my diagnosis is correct. Normally my car idled @ vacuum of -5.1-5.2 psi now it idles rough @ -4.2-4.5 psi. Also every time I shift I get flutter and I'm still on the stock BOV. If I'm accelerating lightly it will flutter, if I boost and push the clutch in it will dump and then flutter. Car never did this before.

So do I have a boost leak or a bad spark plug? I also pulled the p0171 code.

 

Your car does not idle at 5psi of boost.

 

my cars doing the same exact thing. My car feels really slow too. I'm thinking it could be the TB seals but that wouldn't affect the bov.