You don't "set the idle" on these engines, the ECU controls it. Probably the idle air control valve is not working, so someone opened up the throttle plate to keep it running. Proper setting of the throttle plate is so the engine barely runs (400 rpm) with the IACV electrical plug disconnected. Then when the valve is connected a normal idle will resume.

I think the ECU will cut the compressor if the engine is about to stall. This is good evidence that the ECU is still in the loop controlling the compressor. The idle problem is not A/C related at all.

 

Sorry - I should've said that I shortened the throttle cable (by adjusting its position in the bracket) to make it idle where I wanted it to until I figure out the problem.

I'll check into the IAC as well.