Here is what I would do.

Forget about the electronic control for now. Unplug the ECU.

I am assuming the ignition and fuel pressures and fuel volume are in spec.

Clean the ICV and disconnect the electrical plug. No false air past the throttle valve.

Unplug the O2 sensor. ( i would replace the O2 sensor you have been running extremely rich) Get your multi meter and read the DC volts on the control wire coming out of the O2 sensor to ECU. Mine is a green wire.

Get the car running and wait until the O2 heats up. As it heats up monitor the dc volts output from the O2 sensor.

The sweet spot is DC volts fluctuating between .0 and 1.0 DC volts. THIS IS THE RANGE THE ECU CAN WORK and ADJUST THE MIXTURE to lambda -adjust the 3 MM SCREW INTIL THE VOLTAGE IS THAT RANGE.

THIS IS LIMP HOME MODE. What we are doing is isolating the electric control from the mechanical system. If the car does not run right after making this mixture adjustment then you know you have mechanical issues.