Further to my postings over the last few months regarding my 84 
Westfalia that would stumble when the O2 sensor was connected;

I took the bus to VW ($$$!) since they have the authority to provide
a provisional pass for AirCare if I spend $250 on emmisions repairs.
They reset all the fuel system parameters including things like the
CO level, mixture,  and all that rot, as well as test the CAT which
is apparantly fried.  Anyhow since the shop rate is about $75/hr and
I only authorized $250 worth or work, they didn't get too far in
fixing anything, except reseting the FI/Emission settings, and they
also replaced a Crankcase Breather Hose ($35 + install).
'
The throttle switches are fine, the air flow meter intake boot is 
fine, the plugs are good, leads are fine, the rest of the FI is good, 
and various other items which were pointed out to me by the list and 
TSBs were also checked.  I think it had everything to do with the CO 
levels screwing up the O2 sensor readings, in turn screwing with my 
bus' mind.

The stumble is now completely eliminated, and the van runs great.  I
intend to go through testing tomorrow, and VW thinks it should pass
even without the new CAT.  They also recommended I get proper spark
plug leads (of course VW brand...)

I intend to go with new Bosch triple electrode plugs and proper leads 
in January, in the meantime everything is great again, and I will 
post the emissions results later.

Special thanks to all those that helped over the past while, specific 
thanks to Joel for the FI technical information which I used to make 
sure my $$$ went the right avenue in diagnostics, and to guard myself 
against the potential of a VW fleecing.  Also thanks to Dan Houg, 
Harvey Chao, and recently Jack Reed for their true 
experience/solutions.

Happy Holydays.

brian isherwood.
- 'now that I've fixed everything on my 84 I want a synchro 
Westfalia so I can do it all again - and more.'