Agreed above, just to complicate matters a bit more, there is an 'ISC' idle speed control valve,looks like it's at the front of the engine,[have'nt looked, just looking at a picture in the manual] looks like a little motor, has two water pipes connected to it.
Apparently after engine warm up it should make a clicking sound
There are checks given to test if it moves in both directions.
Think maybe we are going in too deep.
When the aircon is switched on does the engine 'idle up' ie increase revs a bit?