[s-cars] By-pass valves

[David Giannandrea]

Coincidentally, while chasing another problem, I just tested my bypass valve
minutes ago. It failed.

The manual (93 S4) says it should hold vacuum for 30 seconds using a
Miti-Vac or similar. It didn't hold at all. It may still be able to operate
but not as efficiently as designed. I don't have any BIG problems, just a
bit low on boost, low on mileage and the failed smog test.

David G.