One cause of a sudden drop in power is a collapse of the innards of the
catalytic converter.  If this has happened you may be able to feel (with
your hand) a difference in the force of the exhaust (if you can remember
what it felt like before) or possibly even hear a difference.  Definitive
test is, of course, to measure the back pressure upstream from the cat which
any muffler shop can do.

Could be a lot of other things too.  Good luck.

Geo

----- Original Message -----
From: "dylan friedman" <insyncro@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, August 04, 2009 3:38 PM
Subject: 2.1 wbxer stubblin' idle

>
> Yesterday I had a great running van.
> Today low on power, idle is weak and chokes until hi revs.
> DigTool checked all that I could and all check out OK.
> No difference when oxygen sensor is unhooked.
> In the process of cleaning all grounds.
> Compression is excellent, Leak down excellent.
>
> Feel free to pmail me with suggestions
>
> dylan