stall, oil pressure on autocheck, go again

[Nathan Engelbert]

My 89 90q has stalled twice at highway speeds, the tach drops to zero, the
oil pressure image comes up on autocheck, and four lights come on under the
autocheck (antilock off, top center, middle middle, middle right, lower
right).  To start the car back up, I had to just turn the key to off, then
back to on and let out the clutch and the car ran fine the rest of the way
home.

Well, tonight on the way home from a concert, the car stalled about a mile
from home and wouldn't easily restart.  Oil pressure and the same four
lights came up again.  I tried to restart using the starter as I was now
stopped.  The car would turn and turn, feel as if it would kick over, then
go back to regular cranking.  After letting the car sit while looking
through the bentley and having tried to start about 15 times, I turned the
engine, starts up as usual.

Each time this has happened, my oil pressure gauge in the center console has
been reading ~5 bar while driving and ~2 bar idling.  Oil pressure senders?
Check and clean electrical connections?

TIA,

Nathan Engelbert
89 90q