So yesterday I changed the fuel pump and they tried it and still the truck did not work it starts and stalls out need help , however my dad was saying that maybe the throttle cable is messed up since it cant keep idle . I already changed the filter,pump and regulator since on the test was delivering only 40 psi after a minute. Lastly is a 99 silverado 1500 4wd 5.3

 

Need more information.

 

Please post make, model, year and detail what it was doing that made you change the fuel pump. Your question is pretty vague and scattered at this point.

 

99 silverado and was loosing pressure dropping to 40 psi

 

the psi was reading to low 40 psi after turning the key with engine off

 

What is the fuel pressure for the new fuel pump?