its not going above 0 psi?...

mine did this. checked all my hoses and wasnt that.

the amal valve wire had come off so it was staying closed so the actuator wouldnt open the wastegate. if the wires are fine on the amal valve check it clicks when u turn the ignition on as it should click if it is functional.

if above is fine you could check actuator, i had this problem again when i fitted a new 1 and i didnt put enough pre tension on the actuator.

other than that could be penny washer not sealing on the wastegate properly maybe?!?!

aaron