What wiring loom, ecu and sensors have you used. I.e are they all matched and from the same system. OFAC or OFAB.

Who installed the wiring loom and is it correct, does it use a FRST loom?

The EFi system hides many issues as it will run with almost all the sensors unpluged, so if you have done an EFi conversion and has a wiring issue or the wiring is not correct you have no real way of checking if all is right with diagnostics or hardware.

These days finding decent working CO pot's are hard too, most of them will not adjust and needs to be changed. So worth checking the wiring to the ECU from all the sensors and pin check each one.