Don,
  Having read the original reports on this on the list about 10 years ago,
this is my take.
The term "Vanagon Syndrome' as it was originally used referred to a
mechanical vibration of the wiper arm in the AFM causing an intermitant
signal to the ECU which then shut down the engine temporarily.  In the
cases studied by the reporting engineers, this typically happened after
driving for an hour or more at steady highway speed.  That is how it
happened to me.
  The plug-in harness from VW and the "capacitor fix" are two different
approaches to a solution.  I believe that the harness from VW contains
active components (like transistors), not just a capacitor.  In any case,
the idea is to filter the output from the AFM to reduce or eliminate the
momentary glitches from the vibrating connection.
   When I had a VW engine in my "91 GL, I solved the problem by adding a
capacitor. I believe that I used a slightly larger value than the 10 mfd
commonly recommended.  Calculation of the RC time constant of the circuit
seems to support this.

Larry A.

On Fri, Oct 18, 2013 at 10:44 AM, Don Hanson <dhanson928@gmail.com> wrote:

>    Like the subject says.   I just saw a few posts about a Digifant inline
> VW powered vanagon traveling the southwest, like I soon will be doing
> again...   He says he's having engine cutting-out problems and someone
> suggested he is experiencing "Vanagon Syndrome"..  I've seen this mentioned
> often before, but it got my attention this time, since this fellow traveler
> seems to be driving a similar Vangaon to mine.   I 'assumed' us inline
> drivers were immune from Vanagon Syndrome...but that may not be the case?
>
>    Anyhow, forewarned is forearmed...or something like that...and when I
> head out around Xmas time to travel the outback west I guess I should know
> what this condition might be and how to go about fixing it, should it ever
> happen to me in my 84 digifant II with a 93ABA block and 92 Jetta top end
> VW inline motor.    Anyone care to outline what this condition is and how
> to fix it when out on the road?
>
>    I have never experienced any weirdness with my engine management, so
> far...(fingers and toes crossed) other than a hinky throttle position
> switch and of course the Temp II sensor..I travel with a lot of spares and
> wouldn't mind having something for the Vanagon Syndrome, should I ever
> encounter it with my rig.
>
>   Thanks in advance,  Don Hanson
>