86 5KCS Sudden Death

[Steve Sherman]

I'm hoping some on the list can offer some advice as to what might be
going on here....  My (wife's) 86 5KTQW died this afternoon as I was
taking it on a test ride.

I had been looking for a slow coolant leak, just enough to lower the
overflow tank to the warning lite stage with 50-60miles of  driving.  I
had cleaned up the engine and checked all the hose connections, and went
out on this test drive.  About 5 miles out I stopped and looked under
the hood.  Everything fine.  Headed back home and suddenly the car
starts bucking/missing.  By the time I am 0.5mi  from home the engine
just won't run and dies. Can't restart it,  so I use the starter to pull
over to the shoulder.

This car has been running fine for some time now, and I have not seen
this behaviour in this car before.  I did see similar things with a bad
fuel pump relay years ago on a VW Syncro I had. Maybe the same thing,
but that was more gradual/intermittent.  Any ideas/suggestions as to
what it might be, and if I should get it towed to a shop or back home (I
have towing ins, but I only get one tow, so if I go home I gotta get it
working.) or things to try before the tow.

BTW I think I did locate the coolant leak while waiting for the ride
home.  There was a steady drip of coolant coming from the bottom front
of the engine.  No wetness at any hose connections, so I was thinking
that it must be a water pump leak (pump is only 3 yrs/25K miles old).
Any thoughts here?

TIA