BTT for this, my problem is fixed (actually has been for a couple of weeks now <img src="/forums/images/graemlins/ignore.gif" alt="" /> )

You can see the culprit in the pic below:



The intake hose seems to be made of rubberized plastic. Mine is going on 13 years old and is developing some cracks where the vacuum lines attach. There is a metal piece in the intake hose that the vacuum line attaches to, and the cracks have become severe enough that it was pulling out and allowing a vacuum leak. I put the metal piece back in, put some high-temp RTV around all of it to seal the cracks, and then wrapped the whole thing in electrical tape. Probably better to just buy a new intake hose piece... but I'm cheap and this works <img src="/forums/images/graemlins/notooth.gif" alt="" />