You might try disconnecting various vacuum lines and blowing them out to clear debris. I've noticed a bit of dust when doing this over the years. Those little restrictors can get clogged. Anyway, I've also always replaced the rubber lines as they age more than the hard lines.

__________________
DS
2010 CL550 - Heaven help me but it's beautiful
87 300D a labor of love
11 GLK 350 So far, so good
08 E350 4matic, Love it.
99 E320 too rusted, sold
87 260E Donated to Newgate School
www.Newgateschool.org - check it out.
12 Ford Escape, sold, forgotten
87 300D, sold, what a mistake
06 Passat 2.0T, PITA, sold

Las Vegas NV