Howdy neighbor. (I'm in Woodstock)

Start by reading out the fault codes for possible clues. The instructions are in the FAQ. You may get some misleading codes, but sometimes you can sort of "read between the lines" for a hint to the problem. Then clear the codes back to 1-1-1 and see what code(s) return first the next time you crank the engine.

Also, check for spark while cranking the engine. If it's getting a good hot spark but still won't start, at least you'll know to start looking toward the fuel system, which will cut the diagnostic process in half.

If you have the Rex Regina system, which you likely do, go ahead and take that big wierd coil assembly apart and clean all the mating surfaces and internal connections. It's a known problem area on that system.

At 265,000 miles it's time for the fuel pump to go bad if it hasn't already. Do you hear it cycle on for a couple seconds when you first turn the ignition on?

Another common problem is the Radio Suppression Relay, which is what feeds electrical power to the injectors. It is usually mounted on the front side of the coolant overflow bottle. If there are two relays there, the second one powers the auxiliary cooling fan. You can swap the wire leads between the two relays as a temporary test. (But keep in mind that if the RSR WAS bad, and you swap the leads, now the aux fan won't work - and it's gonna be about 101 today in Atl.)

Good luck. Get back with what you learn.