Intermittent gremlins... NOT AGAIN!
I would spend a few sheckels and replace ALL of the fuses under the hood. Don't look at the old ones, don't try to save $5 JUST DO IT. It's amazing how many of these gremlins can be killed by simply replacing the fuses.
Next thing to check (In My Humble Opinion) would be the fuel pump relay. Also check the overvoltage protection relay (there's another fuse to replace there!!).
Don't despair and DON'T GIVE UP!
1989 300 E
1992 190-E 2.3