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Subject:Re: hesitation/bucking (was: Re: tested Oxygen Sensor, and...)
From:Mike Collum
Date:Sat, 17 May 2008 13:38:30 -0400

pickle vanagon wrote:
> I guess there is probably no test for this issue short of wiring in the
> capacitor, correct?  Would you say that my symptoms are consistent with
> this problem?

The harness and the capacitor both address what has been called "Vanagon
Syndrome".

The wiper in the AFM wipes the track somewhat hysterically (a rapid back
and forth motion) so, when driving at a steady speed for long periods,
the wiper motion can confuse the ECU and cause the bucking or cutting
out of the engine.  The temporary cure is to shut off the engine and
restart.  What the harness or capacitor do is electrically dampen those
oscillations and prevent the problem.

My '84 7 passenger exhibited what could be described as Vanagon
Syndrome.  I popped the cover off of the AFM and cleaned the track with
a pencil eraser.  The wiper had not worn completely through the track or
else I would have moved the board over slightly so the wiper would have
new surface to ride on.  Anyway, I did that cleaning about 6 years ago
and haven't had the "Symptom" again.

Mike