I appreciate you (Dennis) taking the time to explain this.  I didn't understand how it could be the problem if disconnecting the o2 sensor caused the same symptoms.  Since my problem isn't fixed and I am looking for solutions, I just found this document that I think is great too.  It mostly focuses on the AFM but has a lot of good info and the description of the problem sounds exactly like what I have been experiencing.

www.vanagonauts.com/files/FIxSystemxAFMxproblemsxxxfix.rtf

--- On Wed, 8/10/11, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:

> From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
> Subject: Re: Help! Hesitation on the road!
> To: vanagon@GERRY.VANAGON.COM
> Date: Wednesday, August 10, 2011, 4:39 PM
> That harness has limited success in
> solving the problem and part of that
> solution is the effect of modifying the AFM output. VW was
> wrong.
>
> The O2 sensor circuit is the only circuit that actually
> calibrates to a
> signal, a real voltage, not a resistance change. When the
> signal is weak or
> there is a noise or ground problem the ECU will continue to
> richen the
> mixture until it sees that signal. A bad ground reference
> or a shorted input
> lead will even override the effect of disconnecting the
> sensor. The ground
> reference is the brown wire that travels in the distributor
> harness. Often
> it is connected to a screw at the base of the oil breather.
> The plastic does
> not make a good connection. Move it and if the wire in the
> crimp is brown
> replace a crimp ring terminal. For wire testing do the
> following:
>
> Disconnect the O2 sensor and peel back the outer wire
> sheath to expose the
> outer shielding. Yes this is a coaxial wire.
>
> Key on-Engine off, with a sensitive or digital voltmeter
> measure between the
> outer shield and a good reference point on the chassis.
> Should be real close
> to 0 volts.
> Measure from center (signal) wire to same reference. Should
> be .5 to .6
> volts.
> Measure from center to shield. Should be same as center to
> ground.
>
> Any stray voltage on that shield gets added to the voltage
> setting the O2
> sensor circuit is looking for. So let's say you see .25
> volt on the shield.
> The ECU will not reverse and lean out the mixture until the
> O2 sensor puts
> out ~1.0 volt. Since normal regulation is somewhere between
> .2 and .8 you
> can see where this can mess things up.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]
> On Behalf Of
> george jannini
> Sent: Wednesday, August 10, 2011 4:16 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Help! Hesitation on the road!
>
> I Googled...
>
> VW technical service bulletins regarding driveability
> complaints read as
> follows- The first details problems with Digifant engines
> and the second one
> supercedes the first, acknowledging problems with Digijet
> Waterboxers as
> well.
>
> --- Begin quote ---
>
> Technical Bulletin Group: 24 Number: 92-01 Date: February
> 29, 1992
> Subject: Vanagon Intermittent Misfire Model(s): All Vanagon
> Digifant Fuel
> Injection Engines
>
> CONDITION After driving for 1/2 to 2 hours at a constant
> speed, vehicle
> experiences lack of power, cuts-out or stalls, often
> accompanied by bucking
> or jerking of the vehicle. In ALL cases, the vehicle will
> restart
> immediately.
>
>  This symptom may not re-occur for several weeks/months.
> Inspection by the
> dealer results in nothing conclusive. Some air-flow meters
> may experience a
> vibration resonance of the metering potentiometer wiper
> during extended
> constant driving. This resonance causes the air-flow meter
> to supply an
> intermittent signal to the Digifant ECU. The ECU will then
> default to a
> "no-load" condition and reduce the injection time.
>
>  SERVICE Harness, Part No. 025 906 302, is available to
> resolve this
> condition. * remove electrical connector from air flow
> sensor (see Figure
> 24-174) * install converter assembly, Part No. 025 906 302,
> between harness
> and air flow sensor NOTE If customer complaints persist
> after performing the
> above repair, contact your Zone Product Support Specialist
> (TSM in Canada)
>
> ____________________________________________________
>
>
> Technical Bulletin Group: 24 Number: 92-02 Date: April 30,
> 1992
> Subject: Vanagon Drivability Complaints Model(s): All Water
> Cooled Engine
> Vanagons SUPERCEDES TECHNICAL BULLETIN 24-92-01 (February
> 29,
> 1992)
>
>  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
> recur for several
> weeks or months.
>
>  SERVICE To resolve this condition, wire harness Part No.
> 025 906 302,
> should be installed. This harness provides improved signal
> voltage
> stabilization. * remove electrical connector from air flow
> sensor * install
> wire harness, Part No. 025 906 302, between main harness
> connection and air
> flow sensor connection.
>
> --- End quote ---
>