Hello everybody. I am presently in the mid of diagnosigning an extremely hard case. 1999 Honda Logo Ga3, serious fueling problems with serial O2 sensor "failures". Without bothering you with the details I have finally narrowed down the problem to a couple of causes, and I will be checking them over the next few days in the evening, but one of these possible causes is the fuel pressure regulator. Which would be quite the problem.

Honda part # is 16740-P7A-G01 and is listed everywhere as NLA. Apparently it's not shared by any other model, Honda or otherwise, so I have no clue what to install in case I have to replace this part. It really looks like a period standard Civic or Accord part but unfortunately I haven't any at hand to try it out. I can post picture and (from workshop manual) fuel pressure values if this helps. I don't really know if it's worth installing a fancy adjustable fuel pressure regulator since it's likely worth more than the car itself.
Any help would be greatly appreciated!

 

I am posting this in case somebody has a similar issue. Fingers crossed after over two months it seems I managed to fully cure the issue.

The cure was to fit both an FPR taken from a low mileage scrapped car and a new distributor. I hope this will be the end of it, but I fear I may have a leaking injector as well now.
At least that's not a big deal as I have a whole low mileage injection rail at home ready to go.