I think once it cuts out the only ignition signal you can measure is the the 12 volt power source at the coil plugs. There should still be power across pins 2 and 3, the 2 thicker wires.
Sorry, I mean when cracking the engine, are all coils output the sparks when cracking after it shuts down?I think once it cuts out the only ignition signal you can measure is the the 12 volt power source at the coil plugs. There should still be power across pins 2 and 3, the 2 thicker wires.
It might be good to know that no spark after the engine shut off, at least most likely it is not related to fuel system stuffs. If no spark, assuming no spark on all three coils, not just particular one coil you tested. If say, one coil failure after it is hot enough, 6 cyc -> 4 cyc, probably cannot start again, so maybe can check all three coils with no spark after engine shut off. If no spark for all three coils, first check could be the IFS, and as @Baba Galant said bridging pin 3 and 4 to bypass the IFS, but you said you did that already. Maybe you can also check each of the coil pin 3, and see any voltage, maybe 12v or 5v when cranking. If no voltage at all three coils, check back on the ECU side, C-31 pin 10,11,23, and again to see any voltage when cranking. Normal, should have some voltage when cranking. If no voltage at all, that means ECU not sending any signal out at all, and need to check "upward" and check what cause ECU sending no signal to coils.
I also suggest you to check the common ground as well, that's the ground point near the ABS pump, wiper motor. If rusting or bad grounding, it might also be a problem. Also check there is good ground on each of the coil pin 2.