My fuel pressure keeps dropping off under boost. I'm running a rewired Walbro pump. I checked the voltage at the relay and at the plug on top of the tank and they're both at around 14 volts at idle. My fuel pressure at idle is 40 psi and it drops to 35 psi under boost. When I jump the plug in the engine bay I don't get more then 45 psi. I've tried 3 different vacuum/pressure sources for the pressure regulator and it didn't make a difference. When I pinch the return line the pressure goes up. So is the regulator bad? I had this problem with my old rail on, so I bought another. Is it just bad luck to get 2 rails with the same problem?