Idling problem

[chosen 1 den]

Idling on my Chim 4.0 has suddenly become a problem, veering up to 1,600 rpm for a few minutes then suddenly correcting itself. Had the car serviced by reputable indy recently and that included a clean of Stepper Motor. Grateful for any suggestions as to how to resolve.

[snorky]

they may have cleaned stepper but did they clean the orifice it came out of....may be full of sh*te....???