[jayoldschool]

Yes, idle could be too high. Also possible (and likely): sticky carb linkage. Take off the complete air cleaner top and bottom, and (with the car off) move the linkage through its complete range of motion. See if it returns all the way to closed. Get some good carb cleaner, and give everything a liberal spraydown. Keep working the linkage while spraying to try and free it up if it is gummed up.

Another possibility is if it has an AC idle boost solenoid. That might be sticking out, making the idle high.

Can you get something to measure engine speed?