Update:
No pics, I'm not worried about my piping at the moment, it held up great all week through normal driving and some proper pulls. Gas mileage has improved significantly as well, likely got over 300 miles on a tank for once.
Fuel trims fully set in at -3% at idle and +7.4% under load, still higher than I'd like it to be, considering it was sitting under 3% after my fixes. Fuel adjustments may just be the tuning. Canned tunes will differ LTFT's. Not to mean there are no problems of course. There still may be something causing the addition. Especially if you noticed a better trim than 7% previously.
The car had two soft codes stored as of checking this weekend. The first was for the Diverter Valve, a code always thrown by it not knowing what the GFB DV+ is doing. P0249 or something along those lines, it's always in there. I don't think you should be having a constant P0249 code just because of the GFB DV+. I have never heard it will always code. I believe it is actually for the N75. Can you test the resistance across the two prongs of the solenoid? Should be 25 ohm minimum. If you see no problem there,, then there must be an issue with wiring to it elsewhere.
The other was more troubling, I believe the code was P0087, it was rail pressure below threshold, intermittent. Which from my research is a PITA and very difficult code to diagnose and track down. I've been noticing my top end still has stutters, and it didn't feel as fast over 80mph the longer the period of time after my fixes I drove. My intuition says there is some fuel starvation somewhere after a certain RPM still, I at least know it isn't fuel trims or ignition causing the issue. That leaves the HPFP, related sensors, the devious rail sensor, the fuel filter, or the LPFP. What are the pressures? It would be nice to see low and high pressure; specified and actual...on a graph preferrably. But some data to see is good.
Breaking down those listed above, the HPFP is still rather new, I just changed the cam follower, and my cam is not in bad shape at all, although I very likely have an A revision cam just by my build date/VIN.
The thrust sensor on the HPFP I have replaced, I think twice, and the most recent one was when I changed the load of sensors to correct my trims. That's out.
The devious rail sensor I'm going to try a D revision part, the orange one, and see what effect that has while logging the car, I want to see what that sensor does to my idle pressures and go from there. This is my likely culprit.
The LPFP is original, but my duty cycle at idle is in spec, and considering while logging my car and viewing measure blocks I have never seen a great or concerning variation in spec vs actual rail pressures, I don't think my LPFP is struggling to keep up. I suspect you will see a difference. In the higher, near redline rpm's the specified/target should remain 4 bar or more. Specified never drops below that. If the actual is dropping below 4 bar, post that data. You have to see data at near redline to get accurate data. If you then see the duty cycle at 92% yet the actual pressure drops below 4 bar...what does it drop to? I will watch this more closely this week while I have my laptop with me. Do you only watch? Or do you Log?
The fuel filter was changed when I did a full refresh on the car, about 40k miles ago now, so maybe time for a change. It was a mann-hummel filter with the 6.6 bar rating on it, so that should have been correct. This time around I have another one sitting around, a different brand, but should still be the 6.6 bar, maybe worth throwing that in while I'm at it.
At any rate that's all I can think of that would be left to trigger the code, mind you this is a soft code, the car never came up with a MIL from this, although I could feel it getting choked up and slower as time went on this week. The fuel trims still seem to be adding some fuel, likely when I stomp on the throttle, so maybe there is still a fuel delivery issue that the O2 is picking up on. It doesn't lean out under load, it never has. I just find it odd this creeps up after having all four injectors actually work properly for a week, and fuel trims have stayed in spec the whole time.
Feel free to toss in some other things I might be missing.