Just below the TBI there is an electrical connection with 4 wires, 2 wires go to two different solenoids/actuators. Disconnect the connector. One of the devices should be for air injection, and I do not recall what the other one does. It should run a little richer, because the air injector is not connected (but it is not injecting air either). If this works, either buy the parts, run with the connectors off, or cut the wires to the air injector and run with the other one connected.
I ran a couple of months with the connector off. Mileage did drop from 22 indicated to 20 indicated.