6.0L V12 - sudden rough idle, loss of power and DTC FF36

Waiting for someone to chime in, I did spend more time reading and searching. Conflicting views and no clear path forward.

Many suggest that the FF36 points at injectors (B-bank) not firing properly due to an O2-sensor being faulty, but I have tried playing with the injectors and know that the 36CU flags FF44/FF45 when something is amiss on that circuit.

Another lister claimed that his problem (FF34 A-bank injectors) was solved by replacing the ignition amp

Anyone else that had FF34 or FF36?

Any ideas how to diagnose the condition? Ways to pinpoint the problem to a specific component (I still have the old O2-sensors and I can easily swap them in – btw, the replacements were put in last summer when I had problems passing the emissions test:

which probably was another early warning that I have a problem lurking)

Looking back, I am sure I am missing something and need your help. The underlying reasons for what’s happening are not understood.

Any suggestions are welcome.

Steve