97 Rodeo won't idle when hot

My '97 Rodeo (3.2L V6) runs great. But after initial warm up it won't idle down.
Once warm the idle speed stays around 1800rpm. It makes no difference if it's in gear or in neutral (in gear you really need to be on the brake peddle at a stop sign!).
I've read the posts about cracked intake manifolds and bad intake manifold gaskets, but this just doesn't act like a vacuum leak. I've seen a lot of them over the years and they almost always cause a rough idle. This is smooth, just too fast.
Anyone seen this?

Yup, it is most likely the rubber boot on the trottle cable that is breaking down and gumming up the cable and making it stick. There was some photos of it recently ... I'll look for them ....

here it is:
it includes great photos too:

http://www.automotiveforums.com/vbulletin/showthread.php?t=333904&highlight=cable

could be the throttle position sensor. Even at warm up it should not rev to 1800 maybe 1300

Sorry guys.
It's not the throttle cable. The boot is fine and the throttle plate actuator cam (at the end of the throttle cable) is solidly against the idle adjust screw. The adjust screw is tight and there's no sign that it has moved.
Any other ideas?

check the operation of your coolant sensor. if you have a multi meter you can check the resistance of the sensor. if it is high when the engine is warm then it is not working right. you will have to check the specs if not i can get the values off my rodeo