fuel pressure should be set by the stock pressure regulator, something like 60psi but check the owner manual

the owner manual may suggest some things to check if running so rich also

i would not be fiddling with the fuel pressure, thats not a good idea

2 things set the amount of fuel going in;

fuel pressure...this should be controlled by stock pressure regulator

the duration the injector is open each time... this is controlled by ecu

the ecu decides how long to open (how much fuel) based on the readings from the sensors... AFM, TPS, O2, Temp etc... there must be an issue with the inputs it receives and therefore one of the sensors

perhaps borrow sensors from someone else and start swapping them out till you find the issue

just thinking while i was writing... the CA18DE and DET injectors are different resistance or impedance.. perhaps you are using the DE injectors?