Donna,

                I had a similar engine problem which turned out to be a
partially broken wire at the connection on the back of the alternator. It
didn't look broken until it was unbolted from the connection. This is the
big red wire that is connected on a stud terminal with a 13mm wrench size
nut and I believe it is connected to the battery and is " hot " . So you
need to disconnect the battery to look at this connection. My van would run
fine and then just cut off and on until it finally stopped running. When I
inspected the wire it was not completely broken, so I cut off the frayed
portion and crimped on a new ring connector and that solved the problem. I
noticed while the van was having this issue that the tach would drop to zero
when the engine cut off.

Another time I had this same problem it turned out to be the ignition coil
going bad, so definitely check that too. And another time it was the
ignition switch (electrical portion ) As usual there could be many culprits
but I hope this helps.

Rick

'90 syncro westy, '91 syncro tintop, '91 carat