1993 Cadillac Seville

A couple of possibilities you will need to determine. When it don't start, do you still have spark? Pull a plug wire at the plug end, insert a phillips screwdriver and hold it within a 1/4" of a good ground. It should spark, don't back the screwdriver too far away, or you will be the ground and get a shock(if it has spark). Next you will need to check an injector for a pulse, this is best done with an injector test(noid) light. You are losing one or the other, if you have fuel pressure. If you do have spark, the engine should attempt to start with a shot of starter fluid. If no spark, you could be dealing with an ignition module or pickup coil(both in distributor), an ignition coil, cap, rotor. If you are losing injector fire, but have spark, you might be talking an ecm.