Before you starting pulling or replacing expensive components (or get out the hammer) inspect all of your vacuum connections. High idle is a common symptom of a leak.

Look at your "economy" gauge. It should be pegged to the left at idle. If it is not a vac leak is certain. Redardless, look closely at your soft rubber vac connectors. Don't forget the hidden one between the intake manifold and the firewall. It is often the first to go because of the hot, oily environment.

Whatever cures your ills, please post the repair so we can add to the data base.