The microswitch on the throttle linkage should be closed when the throttle is closed, and when you press on the throttle the switch should open before the throttle valve begins to move, so it's a matter of adjusting the linkage to achieve the above condition.

The throttle postion switch on the butterfly shaft and the microswitch must both be closed for the ECU to go into idle speed control mode. There is a three pin TPS connector on the top of the inlet manifold ahead of the air flow meter - idle, WOT, and ground, and you should check it, too.

A few years ago I lost idle speed control, and it turned out the TPS was not sending an idle signal. It's difficult to access, so I just thoroughly cleaned it externally with a spray bottle of mineral spirits and old paint brush, then gave it a shot of WD-40, and it's been behaving properly ever since.

The microswitch also controls fuel cutoff on trailing throttle. That's why the throttle pedal movement needs to open the switch before the throttle valve begins to open. This feature turns the fuel back on before the throttle valve begins to open, so the transition is smooth. The service information has data on how to adjust the throttle linkage, but I adjusted mine for minimum pedal travel to open the microswitch to minimize the "dead spot" in pedal movement before the microswitch is opened and minimized the distance the pedal must be moved to begin opening the throttle valve after the microswitch is opened. It makes initial throttle application feel more linear.

You should also check that the microswith has continutiy when closed as indicated by a slight click that you can hear.

Duke