George,

I checked with my mechanic about this.  He worked for the local
dealership at one point.  He said that this part is to fix the "vanagon
syndrome" hesitation/bucking problem with all Digifont (this was before
Digijet, right?) injection engines, including Rabbits/Jettas.  The same
part, he says, is used on the cars as well.

I know I had this problem before and suggested that I should get it.
They didn't seem like they wanted to do it.  I had a ton of work done to
the van just now, so I think they are sick of me.

Btw - my van was stalling constantly, had a ton of power and bad gas
mileage (14-16 MPG).  It had the O2 sensor disconnected and the muffler
came apart.  In addition to the Boge springs and Bilsteins, they
replaced the muffler, fixed some ?air-flow? Tubes, and reconnected the
O2 sensor.  It runs as it did before my "vanagon syndrome"
hesitation/bucking problem - no power.  No stalling though, which is
good.  If my fuel consumption goes back up to close to 20 MPG, I will be
happy with no power until this engine dies and therefore justifies a TDI
or 2.5 Subaru boxer replacement.

I also learned some more about the "computer part" that I thought had
fixed my "vanagon syndrome" hesitation/bucking problem.  After the
hesitation/bucking and stalling, my other VW mechanic disconnected the
O2 sensor and a "computer part".  I found out that this "computer part"
is used to set up the motor.  If you disconnect it, the engine will
change to default settings which, evidently, gives you more power and
negatively affects fuel consumption.  For me, this eliminated my
"vanagon syndrome" hesitation/bucking problem and gave me more power for
those hills.

Disclaimer:  I know nothing of cars, their internal workings or myself
and may have misunderstood my mechanic or otherwise not written this
email in a coherent manner.

Dana from PA
85 Westy with 235k miles
01 New Beetle TDI

-----Original Message-----

Has anyone tried VW part number 025 906 302A in the wiring harness
between the air flow sensor and the wire harness?  The fix provides
improved signal voltage stabilization.  I ran into this bulletin on the
microfiche from ALLDATA.  The bulletin was dated April 30, 1992.
Superseded Technical Bulletin 92-01.

For all water cooled engine vanagons.
Condition: After driving for an extended period of time at a constant
speed, the vehicle may, on occasion, experience a deterioration of
performance which may be accompanied by a hesitation or surging.

In many cases, after turning off the engine and subsequent re-start or
without having taken any action, the symptoms disappear.  These symptoms
may not re-occur for several weeks or months.

The schematic shows it to be some type of transformer.

George