2000 Daewoo Nubira Nubira High idles speed - where is the s

Hello

Having just aquired a Nubira CDX estate 2 litre automatic I have found that the idle speed is around 1450 rpm.

The previous owner stated that it had been like that since she had it (about 10 months)

Reading this forum, I suspect that the stepper motor may be at fault OR there is some kind on air leak.

Can someone please tell me where the stepper motor is located within the engine and how I might diagnose a possible fault before replacing it.

Thanks