CIS fuel systems are basically mechanical in design. Fuel pressure is the key to correct operation.

The system you have is CIS-E that means electrically enhanced basic CIS.

Since the car seems to run "good" w/o the electronic enhancements?
Most likely a bad input from that system.

Testing signals from temp sensor, O2 sensor, & air flow positions sensor would be a starting point.
Also making sure that the O2 sensor has control of the mixture, Lambda reading

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