Realy or coil

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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