On the subject matter of vacuum lines....At about 10 years a lot of the neoprene lines harden and crack, especially those close to hot engine parts. Here's an old trick - a PITA but it works. Pop off the lines one by one. Snip off a quarter inch or so and put the line back on. Doing so gets you into "new" hose softness and inner diameter. Look close for cracking when bending. If the lines show surface cracks, replace even if they are not leaking - they will.

trafdlo