This is a 1992, yes, with a 4.6L V8? I have a great answer if it was only a year earlier, with a 5.0L V8...but this is a different animal.
You could have a fuel pump or PCM relay issue. You could have a fuel pump issue on its own. You could have a sensor issue - cam or crank. Hard to say until testing is done.
is the engine temp running hot? or runs for awhile and shuts down?
will it crank over after it shuts down? there is a number of problems that can cause this
had a 92 grand marquis stop running every 30 miles turned out to be a tank of bad gas had alot of water in it
you can run tests yourself the 92 is still OBD-1 with no special tools other than a jumper wire and reading the flashes of the check engine light most manuals available at auto parts stores for about $15 will show how to do this. hand held scanners are also availble range in price from 30-300 the cheap ones just flash and you still need to look the codes up