I am having a few issues. I usually play my radio kind of loud so I don't know if what I am hearing is normal or not. Basically I'm driving with my AC on and while driving the car is making a loud noise kind of like releasing pressure. I had a blow off value before but do not now,but the noise sounds like a blow off value. It is only noticeable when I am running the AC. The car does lose some horse power when it makes this noise. Anyone know what it could be? The turbo or maybe the AC pump? Anyone else have the same trouble. I have a 2005 wrx. Its all stock no performance parts yet.