Fuel issue need help
 

So I'm having some issues with my wife's s60 2.5t, we have already replaced the fuel pump in the car and a new fuel pressure regulator on the fuel rail, but for some reason the car is wanting to bog out when I give it throttle the more I press the peddle the more it wants to fall on its face iv hooked up a scanner to the obd2 port and when I hit the gas the psi of the fuel drops from 43 psi to 5-8 psi, the only way I can get it to even drive down the road is to unhook the fuel pressure regulator and the scanner reads 111 on the psi but it still doesn't perform like it should still wants to die when I give it to much throttle but if I give it just a little throttle it will get up to speed, but still randomly dies wile driving down the road if I let off the throttle to adjust my speed to where I have to put it in neutral and restart the car wile costing and then put it back into drive any help would be much appreciated