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.