man that is pretty strange... so you have still not found the Vac leak? hmmm.... one thing you should check would be the BOV or Diverter valve for the charger. A friend of mine had a similar problem on a Civic turbo, apparently his BOV had two nipples on it. I think it was a Greddy Type S, and we ended up using the lower nipple instead of the upper one??? It was 3 years ago, but just some food for thought. You may have NO leaks, and it could be whatever you are using to relieve the pressure.