I tend to focus (incorrectly maybe) on whether or not a worn spot on
the AFM resistive strip is causing a voltage drop out; I tend to
forget that the real potential offender is most likely oscillation at
the wiper causing inaccurate values being sent to the the ECU. All
that said, did you measure your AFM for voltage or resistance drop?
All that aside, your post reminded me of this thread on the samba
about a failing throttle switch:

https://www.thesamba.com/vw/forum/viewtopic.php?t=455400&highlight=

Maybe dirt road driving would exacerbate this type of issue?

Neil.

On 9/22/17, Alistair Bell <albell@shaw.ca> wrote:

> I’m not completely sure that adding the capacitor to the AFM has solved the
> problem, but so far it looks like it has.
> Background, for about 5 years I’ve had a very very intermittent running
> issue with the stock 2.1 motor in my Syncro. Symptoms would be bucking and
> hesitation when applying throttle. At wot the bucking would stop. At idle,
> motor ran fine.
>
> This only happened on summer trips, mostly rough logging roads. Occasionally
> it would happen on hwy when returning from rough roads.
>
> Sometimes the problem would come and go within a day. Every time the problem
> would be gone the next day when back in town.
>
> Never happened around town, never happened in winter. Never happened on long
> summer Hwy trips.
>
> So it never quite fit the pattern I had read about regarding the classic
> vanagon syndrome.

-- 
Neil n

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