Air fuel control derate?

[Rockycoon75]

I have a 871 that has been mm'd. The last week it has been acting like it is starving for fuel sometimes when leaving a stop or after coasting for a few minutes. I hooked up insite and ran it on monitor for about 4hrs. When it would act up it was showing air fuel control create. I was playing with different things and if it got over 1800 in the low side it would show noise derate.
Idle fuel pressure is 260
Cruising is 268-272
Pulling a hill 270-276 generally
In 4 hrs the lowest it went was 255 highest was 279

I initially thought it was bad filters so I changed them when problem started. No change then looked for it sucking air. Changed primary filter housing but problem still exists.

I'm kinda thinking it's either regulators or gear pump but not sure.