Your regular mechanic is off his rocker.
The only magnetism going on inside your distributor involves a
spinning, metal cup, that has 4 gaps in it. The "Hall" sensor is
triggered by these gaps, and tells the computer to fire the appropriate
spark plug.
Timing is controlled grossly by the position of the distributor's body
in relation to the engine case (and some other, purely mechanical
settings), and finely by the engine computer, if it's supposed to do
that (I don't recall if Digifant does).
Just from reading the 1.76 million posts to this list involving weird
behavior like your van's, it sounds like Vanagon Syndrome or a coolant
temp sensor.

-Simon

On Jul 11, 2004, at 9:58 AM, Jim Heissenbuttel wrote:

> First of all, I am a novice, so if I use the incorrect terminology,
> please forgive me. I also apologize for the length, but I am desperate
> at this point and need to get this issue resolved this week.
>
> My van has been experiencing what my regular mechanic has called
> "erratic retardation."To the driver it seems like at random times
> (usually the most critical) the engine does not have the power, it
> sputters, and acts like it will die. There is some stalling, poor
> idling, and even backfiring at timies. It seems like when this loss of
> power occurs, stepping harder on the gas the the wrong thing to do,
> while letting up (almost completely) will result in a slight return of
> power, but not back to normal. After some time the engine will go back
> to normal operation. Stopping, turning off the ignition, and restarting
> does not seem to help. Usually, I pull over to a safe spot, a gently
> coax her back to running normally by alternately running up the revs
> and then letting off.
>
> I have been given a very complex explanation about how there is a
> magnetically active paint inside a particular part of the distributor
> that is critical to the advance or retardation of the timing. He has
> also told me that this paint is no longer made and that all of the
> remanufactured distributors may or may not have problems with it. His
> explanation was that the only way to fix this was to buy a NOS (New Old
> Stock) distributor. I have used this mechanic quite a bit and I trust
> him. In addition, he works solely on VW and mostly on Vanagons, so I
> think he is very knowledgeable.
>

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