1991 Oldsmobile Cutlass Engine cranks but no start

Car died while driving this morning. Engine cranks but will not start. When key is turned to on position you can hear fuel pump relay click. Can hear pump run for about 2 seconds, pressure at fuel rail is 42 psi. Can hear injectors clicking while engine cranks. There is 12v present at the injectors and at the ignition control module, coil packs check ok with ohm meter for primary and secondary resistance, plugs and wires are less than 8 months old, but spark appears to be weak when tested with a spark tester. Crankshaft sensor ohms out in spec range from the fitting that connects to ignition control module. ECM is new (was replaced last week. After car died the first time). Checked ignition system out last week and could not find a bad component, reassembled it all and engine cranked and ran fine. For 5 days. This sounds like a short somewhere to me. What do you think? Is a bad ignition switch possible?