I'd agree fuel issue certainly possible but for another possibility, as an off hand bit of diagnosis, assuming it is a stick, about 15-20 seconds into it acting up, push in the clutch, flick the key off for 5 seconds, turn it back to run (don't crank obviously), let out the clutch and see if you "reboot."� Don't actually stop motion and restart the car.
�
If so clean/replace all your grounds on the head, ground strap body to head/engine, and clean all the connection on the ignition system (module, dizzy, stabilizer.)
�
John
�
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� On Mon, Jan 23, 2012 at 2:16 PM, jon durham <jon_durham@knology.net> wrote:

> My 85 Vanagon easily starts. But after going about a half mile, the
> engine begins to barely run, sometimes back firing, This goes on for
> about 3 minutes but then goes away. Sometimes if I stop the engine and
> then restart it, the symptoms go away as well.
>