Pulled the final fuel filter at the inlet of the AFP servo to check for debris. Had to remove the filtered air box to have enough room to re-safety the inlet after inspection.
It was hard to see inside the fine stainless mesh cylinder where the fuel comes in. The filter element is firmly (permanently?) attached. Didn't think it wise to try more than gentle pulling or twisting force. Shone light thru it and saw nothing that obviously impaired flow. Probed (gently!) with thin piece of plastic and retrieved nothing. I'll ask AFP if the thing is supposed to come apart, and whether, in future, it would be good to work up a fixture to back-flush the filter.
The hardest thing was, of course, re-safety wiring the bloody thing. One of the two capscrews is tied to a third screw head that already has a safety partner. After a long search for orthogonal holes (which weren't there), I realized there were other safeties where the wire looped completely around a screw head, completely behind the safety going thru the holes. After that, it only took the usual 10 feet of wire before producing a satisfactory result. :::8^0
The FAB went back on without problems. The ring around the air intake had it's tightening screw loc-tited per AFP's guidance, and the four bolts securing the top plate to the ring were re-loc-tited. I'm OK with my decision not to add tabs and safety wire in case the cinch bolt backs out.