B5 - Vacuum Test -- Catalytic Converter(S) On/Muffler(S) Off
^ Turn engine OFF.^ Reconnect exhaust system at exhaust manifold(s).
^ Disconnect muffler(s).
^ Repeat vacuum test.
^ Is the manifold vacuum above 16 inches of mercury?
YES -- Replace muffler(s).
NO -- Replace catalytic converter and inspect muffler to be sure converter debris has not entered muffler.