Mine started as you describe, a rattling in the converter.  It let go
suddenly one day on the freeway.  The symptoms were extreme loss of power,
and odd whistling from the engine.  We pulled off the freeway, and my wife
revved the engine while I felt the tailpipe pressure, which was almost
zero.  The pressure blew out the gaskets at the joints where the engine
pipes meet the connector for the single pipe to the cat.  The solution? A
broom handle!  Pound out all the broken matrix.  Be careful to get it all
out, as well as any pieces that have fallen into the muffler.  I haven't
had to pass emissions yet, but I'm guessing the converter will have an
impact.

Danno

67 double cab
78 westy
87 syncro
87 jetta

Die Busbesitzer Gruppe:
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----------
: From: Seastoner <rfergus@richmond.infi.net>
: To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
: Subject: Catalytic Rattling
: Date: Friday, May 02, 1997 5:48 AM
: 
: I have a feeling the catalytic converter has broken loose and is 
: rattling around in the muffler assembly. I had heard this noise 
: before but now I'm experiencing a loss of power and a deeper lower 
: sound when acelerating. Can the muffler and catalytic converter 
: effect the aceleration? Is the O2 sensor able to act correctly in 
: this situation and will fixing this be likely to improve my gas 
: mileage as well? Thanks for any advice,
: 
: Rick
: 85 Westie {Stella}