when do the problems stop???????

Today I installed my Aeromotive FPR. Its great, it actually keeps the fuel pressure at what I set it at unlike the HRC thing. Also my boost controller started working again for like the 4th time and I took the car out and as I was trying to see how the car handled at 9psi boost the car started bogging down at 5krpms. 1k-4.9krpms its fine...5k-5.5krpms it bogs down 5.6k-7.2k its fine. A ton of power during all rpms except 5-5.5k. Whats happening here? I had my fuel pressure gauge in my face and its getting 110psi. Thats pretty much what it should be according to HRC but why is it screwing up at 5k?? Ive tried everything I can possibly think of with my S-AFC...leaning it out and richening it up but nothing. Still bogs at 5k. I would think its the injecters but at 6k its fine. Why just at 5k? Any thoughts would be GREAT..thanks!!