Why will my engine not accelerate unless I unhook the vacuum on the map sensor?

I replaced the pump myself and an update on what's going on if I block off the return line I get pressure and truck runs. Only thing I can think of is that the fuel pressure regulator is bad seeing as when the return line is open my fuel just travels thru the line straight back into the tank and I get no pressure at Schrader valve.

Hmmm I have checked all other vacuum lines and don't see any kinks or the sort. The truck was running fine until the fuel pump went out and was replaced but now it seems issue after issue lol

Hmmmmmmmmmmmmmm............yeah.

Okay I have replaced fuel pump and fuel pressure regulator but still the truck will not run right unless I block off return line to tank. Can anyone steer me to a fix because with return line blocked I seem to be using three times the fuel.I know it sounds familiar because the problem still hasn't been figured out.