Guess its a problem of either the crankshaft or camshaft sensor or the ignition control module?
Of the 2 sensors, the
camshaft sensor would be most likely problem.
I say that because if crankshaft sensor was bad it wouldn't fire any of the three coils, sounds like the one firing is the 1 & 4 cylinder coil. That coil should spark for ever revolution of crank, once for #1 cyl and once for #4 cyl, so it would seem fast when cranking.
As you may already realize crank sensor trigger plate has three evenly spaced flags, one for each coil. But ECU has no way of knowing which one is for which coil, without using the cam sensor pulse
in conjunction with the crank sensor to determine which one is for 1-4, 2-5, or 3-6 cly coil. So without a working cam sensor, the ECU might only fire one or no coils at all. Also with the cam sensor not working the ECU can’t determine which cly needs fuel injector to fire, which is only done once per ever 2 revolutions of crank, so you could have arbitrary firing of injectors as well. Hope that helps you understand operation of the two sensors.