60to0in0seconds

I have been battling this "limp home mode" problem for awhile now and i think i've finally tracked it down to the fuel pump but i'm not 100% sure and i just wanted to get some feedback before i go and order the new $250 bosch pump.

I connected a fuel pressure gage to a "T" fitting in the line going to the fuel rail. At idle the pressure was 40psi (alot lower than what the Bentley calls for). When i revved the engine (parked no load) it didn't change at all and the limp mode hits at about 3800rpm every time regardless of boost, speed, temp, etc.

I guess my question is, although my fuel press regulator holds vacuum, could it somehow be affecting the pressure by bleeding off too much to the return line??

Thanks in advance!! Any help or other suggestions would be greatly appreciated!!! I have been fighting this problem for a long time and would love to solve it!!