Idle Issue, checked checklist

[stition]

Hello, I've got an 85 Mustang GT, carburated, and am having high idle problems when the car is warm. Idles great at 900rpm when started, but once I drive it hard or during extended trips on the highway at 65+ it'll idle at about 2k rpm. The choke, doesn't work properly, I can manually close it or open it, but it won't operate based on engine tempratures. After the car cools down it'll idle back to normal.
I replaced the stock thermostat with a 165 degree one, which I realize now is a mistake, and will replace with higher temp soon. Could this have any impact on the idle speeds? The car runs cool normally. Thermostat was replaced a couple months before this problem appeared.
Purely carburetor problem maybe? I have no idea what's going on with carbs. This is my first vehicle.
Also, I'm pretty sure my power steering pump is going out, it's beginning to whine, and the wheel that the belt spins wobbles about 1/2 an inch. I'd like to eliminate power steering completely, is it a simple process of removing the pump and running a shorter serpentine belt?
Do louvers on the hatch help stop the interior from heating in the sun significantly?
Thanks in advance for any help.

 

[jrichker]

The Surging Idle Checklist is only for EFI cars.

If your car has an electrically operated choke, check the wiring for the choke heater. Make sure the choke is all the way open when the engine is warm. The fast idle cam works to speed up the idle on carb cars, and if the choke doen't open all the way, the fast idle cam will cause the idle to increase beyond normal speed.

The other possiblity is a vacuum leak. Almost every one of these old cars would benefit by replacing all the vacuum lines: they get brittle, crack and leak. For less than $10 you can buy all the vacuum hose you need to redo all the vacuum lines.