Tom,

I've been having the same problem with my 91 Ecodiesel Jetta.  Same
exact symptoms.  Starts just fine when cold and the glow plugs turn
on, but once hot, cant restart unlesss I wait for a couple hours to
cool it down.  I found I could push start it with ease, so I would
park on an incline each time if possible.  Pain in the ass to say the
least.

After trying various things on my own, like checking the solenoid on
the injector pump, etc, I finially broke down and took in into the
dealer (the only guys locally that really know VW diesels).

Problem:  timing was way, way off.  But, I'm not sure that fixed it
totally.  It still has some difficulty starting when hot.  Mechanic
said he checked everything else out, and if the timing didnt solve
the problem, the injector pump itself would have to be replaced.
Bummer, as thats a couple hundred bucks I didnt want to spend.

G'luck with yours.
______________________________________________________________________________

Kevin and/or Heather

Where have the years gone? Why, into the usual vices of the romantic
idealist: into sloth amd melancholy, each feeding upon and
reinforcing the other, into love and marriage and the begetting of
children, into the strenuous maneuvers of earning a living without
living to earn, into travel and play and music and drink and talk and
laughter, into saving the world - but saving the world was only a
hobby. Into watching cloud formations float across our planetary
skies. But mostly into sloth and melancholy and I don't regret a
moment of it.

Edward Abbey.