I have a 92 chrokee laredo that is losing fuel pressure after starting up and die i have replaced the fuel pump, filter. checked the relay and fuel pressure regulater and now i dont know what to do, can anyone help me out

 

How did you determine the the pressure was dropping.

If you used a pressure gauge please post the exact numbers for:
Key On - Engine Off
Key On - Engine On
Key-Off - Engine Off

 

key on and primed i get 35to40
eniunge running it looses all pressure to 0
and same with key off untiled primed again

 

How abour Key On, Engine On, Vacuum line removed from Pressure Regulator?

Assuming that your pump is still energized with the Key On - Engine On, I'd lean toward a bad regulator.

Try pinching off the return line and see if the pressure stays near 40 with the Engine On.

 

i already have done thatand the pressure still at tthe 35 to 40psi mark but running it still loosing pressure

 

Seems like your PCM is not keeping the pump energized at Key-On, Engine On.

Do you have an FSM for your XJ?