Engine grounds
#5
Check if all of them have constant +12V with ignition ON (pink wires), if they don't then find the problem (blown fuse, pinched wire).
If +12V is ok, check all PCM grounds (PCM grounds the other wire to activate the injector). The PCM has 4 pins to ground (to 2 ground splices).
You may also have a bad injector driver and need a new PCM