P10CF after walbro install

[one30five]

Installed my walbro 255 inline lpfp last night and found some noticeable improvements in idle, low speed rpm surge, and power delivery. Everything feels smoother which makes me think my stock lpfp was taking a shit. I was not expecting to actually feel a difference after installing.

That said, after some WOT pulls this morning (which felt great) I got the yellow engine on a lift light. It would come and go for the 20 mile ride home.
jb4 code reader said "no codes found"

Harbor freight $75 OBDII scanner yielded a P10CF code for rail pressure sensor low voltage. But I have ZERO physical symtoms. Car starts up just fine , I restarted 4x after parking and reading code and no problems whatsoever

My install was by the book and immaculate. Here are some factors that I'm considering though.
- n55 with E50 mix (7.46 gallon 92/5.6 gallon e85 tested at e82)
- I lengthened the power wires that splice together with walbro. I used same gauge wire and used quality connectors AND heat shrink moisture proof wire insulation at all splices.
-the walbro came off the bucket retainer upon install. Steve said it would be fine.

Has anyone had this experience? Any thoughts on the code? Why it comes and goes ? What I may have done wrong on installation? Perhaps too much e85