The idle speed on these is not adjustable. It is controlled by an idle speed motor that is controlled by the computer based on inputs from various sensors on the engine. If you have an idle problem you can try cleaning the air intake passages at the butterflies with a toothbrush and spray carb cleaner. This helps a lot of them. It usually doesn't look very dirty but it is extremely sensitive to dirt in there.
If you still have an idle speed problem then you may have an idle control motor bad, these are a fairly high failure item on Chryslers (and most other makes too)
If you have more questions or need more info write back