After replacing the spyder fi, nut kit, and tuned VE tables because still too rich, my Sonoma surges at light throttle.
Found Service Bulletin 57-65-03A which recommend upgrading my old prom (BHRH) to new (BPLC).
Can anyone help me with a BPLC bin?
Or a BPLB might be of help. The same bulletin recommended upgrading a BHRJ to a BPLB. Maybe I could look inside the bin and figure out the changes made.
Or does anyone know what the changes made were? The bulletin says it is 'to change Emission Axle under S/T Utility'. (whatever that means)
Oh, mine is a 16196395 PCM, but my understanding is the 16197427 is a direct replacement, so might find the BPLC in one of those.

Any other ideas would be appreciated.
Other things replaced, for many other issues on this acquired headache, O2 sensor (was confirmed bad), distributor, icm, tp sensor, map, plugs, wires, cap, rotor, pcm, muffler, cat, exhaust leaks repaired, coil, air filter.
Other things checked/done during all the headaches, fuel pressure, compression, back pressure, temp sensor, vacuum, egr cleaned, iac, vacuum controlled evap canister bypassed, iat, scoped best I can (pretty good waveform, some end of fireline noise), battery voltage noise, grounds, engine clean done by pro shop (2 part, air intake and fuel additive).
I do get spark retard from knock counts (think other noise being sensed). But believe is not the current surge issue as I still have the surging with knock/retard disabled in the pcm (disable by over high temp requirement set for knock response).

Hmm, while I'm asking, after exhausting all I know for continuing to have my fuel trims too rich (the previous owner performed many, unknown repairs), any secondary effects known to result from having tuned my VE tables quite a bit to compensate for rich trims? I originally changed my injector flow rate to shift all my trims less rich, worked, but then found out my VE tables wanted to go above 100 for tune corrections (which wouldn't take in TurnerPro, go figure :) ), so I went back to original injector fuel rate to tune. The highest VE cell, before tuning, was 89.5 (4000rpm at 100 map), same cell after tune is 77.7. Other cells follow, with much lower values.

Warning, I'm not an experienced mechanic, but having way too much fun.
Why did I buy? My wife said, it just fits us (with big loving smile), and you can fix anything....

Thanks in advance.