Mark
I have a 91 Transporter Syncro and have an ongoing problem which seems to
be very close to yours. The engine always starts first turn of the key.  It
runs well for about one minute until apparently choking/starving itself. It
doesn't re-start so easily but does eventually.  When it does I apply very
gentle pressure to the accelerator with the idea of keeping it going.  The
revs. then increase out of all proportion so I try to ease off and .....it
stops.  Very frustrating. Once it has warmed up it is no problem.
I have had half a dozen mechanics over the last 12 months try to fix it but
to no avail.  The last one said he'd had sleepless nights worrying about
it!
New items recently fitted:-
Radiator, 4 injectors, air filter, pressure regulator, fuel filter, airflow
meter.
Have read Thom's suggestions, Thanks,
Ron