LOL, I have NEVERRRR had to take the turbo off to do a timing job...scratch that off the checklist cuz that isn't the issue.. If anything check timing, if its off even the slightest bit, it will throw everything off including boost pressure...def check timing...not just with a light, look at tdc versus cam timing marks. I bet that's the case, and if not, def a vac or boostleak..