First thing to but is a Bently manual. Then to set idle mixture you'll need either a wideband sensor w/ gauge or an exhaust analyzer. Since it kinda sounds like you have a CIS-Lambda system, you will have noise from the fuel dist as that is the freq valve trying to work. You could disconnect that and set the mixture and things should be OK. If you still have a CAT, then you might want to gut it or get the system working properly as the reason for the O2 sensor ws to ensure the proper mixture for the CAT to operate.