Does your fuel filter (on replacement) reveal the so called crap?
If not, your tuner can check if there's current fluctuation to the pump > leaning out.
If that's so, a hard wire job may be required.
If the current is steady, it can be the pump itself as happened to my 044. My tuner at Unigroup showed me and another technician how the pump itself was displaying a deficient flow rate.
The parts company asked for the pump along with someone else's faulty 044 to be brought in so that Bosch could test them.
I marked the pump and handed it in, in the Bosch box.
Bosch took over a month with the pump and only at the behest of myself was 'it' returned.
'It' was in the box I had, but it came back without my mark. Bosch said there was nothing wrong with my 044 and said that they would not replace it.
How come they did replace it with 'it', and then deny fault? Is reputation worth telling me an untruth?
I hope you get to the bottom of this without too much fuss. Sorry to digress.