when i start my car it idles ok until i touch the gas pedal.

it is low but what would cause this?

if its the original pump its just wearing out and can't build the pressure required to run car under load

i already replaced the fuel pump and filter when i first started having this problem. with a pressure guage attached to the test port i get about 40 psi when i turn the key to the on position but when the car is idiling its at about 20 - 22. thats not enough pressure is it? Also if i push the valve to release the pressure barely any fuel comes out.

I BET YOU BOUGHT AN AFTERMARKET FUEL PUMP. THAT MIGHT BE THE PROB.NOT ENOUGH FUEL PRESSURE OR RESTRICTION IN LINE WHICH I DOUGHT