Which cylinders are coils h[2]=31 22 31 22 connected to?
Assuming a 1, 3, 4, 2 firing order, and that injectors are wired: 1 = 01, 2 = 02, 3 = 04 & 4 = 08
Then if 22 is firing 1 & 4 and 31 is firing 3 & 2 then we know that we know that we can fire the injectors like so:
h[0] = 02 08 04 01 .. .. .. ..
If 1 or 4 is firing then we know that these cylinders are approaching TDC and that the valve will be closed, so its fine to inject on either of these cylinders, and the same for 2 and 3.
This will mean that you get a much better level of injector control and that the fuel sits in the inlet and evaporates due to the heat of the valves, and as a result you get better idle with lower hydrocarbon emissions, and crisp throttle response.