Narrowed vacuum lines... Now what?HELP!
 

I have been having boost trouble the last couple weeks. It seems I get 5 lbs of boost at first, then at 4500 rpm, drops to 1,then returns to about 2 or 3 for a second then drops steadily to zero till redline. Also, at 2500 rpms, I hear a quick blow of air coming out, it sounds like when you blow across the top of an empty beer bottle (a hollow sound), then as I increase acceleration, a "whoosh" of air is distinctly heard, and increases according to how hard I accelerate. Thought maybe a vacuum line had popped off, but took it to a buddy's shop today and took off the UIM and found no unconnected lines or leaks of any kind; in fact, the hoses were still quite pliable. So, now where should I look to? Any ideas would greatly be appreciated. I have only had my FD for about 2 months now, and I really would like to have it running full strength again. By the way, it's a'93 with 58,000 miles. Thanks in advance.

Justin