Vacuum Line Inspection (MILLENIA S)
WARNING: This page is about a different car, the 2001 Mazda Protege, 2001 Mazda Millenia, 2001 Mazda MX-5 Miata, 2001 Mazda MPV, and 2001 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
Remove the clamps and the hose. Apply both suction and pressure to the engine-side of the hose, and verify that air flows only toward that side. See Fig 1 . If air flows in both directions or not at all, replace the vacuum hose.