My '01 Dodge Ram 1500, 5.9L catches my attention occasionally when I hope out of the cab and leave it idling in Park. It revs and slows down the RPM's quickly, like it has a mind of its own. It isn't severe, maybe from idle up a few hundred RPM's then instantly back down, up again, etc. Doesn't always do this, just occasionally. Any ideas, or is this a concern?
Thanks for any info you may have.

Clean or replace idle air control valve.

Thanks for the info.

Where can I find it, or a manual that describes how to replace/clean it?