The engine is running rich, especially at low speed. There are two sides to a rich running engine: 1. There is more fuel than air; 2. There is less air than fuel (ratio-wise).
I think you could get a little more air flow through the air intake and on into the combustion chambers. Use Throttle Body spray cleaner to clean the throttle plate, throttle bore, and idle air control valve air passages.
It’s possible that the engine coolant temperature sensor (ects) is indicating a cooler than actual temperature. Then, the engine computer adds more fuel, causing a richer running engine. You could measure its resistance, and compare those ohms figures with the ohms/temperature chart in the repair manual.