You might want to read up on the "throttle hang" fix from the FAQ section on home page, although I thought it was only a problem with mtx, and not atx, equipped cars.

http://www.contour.org/FAQ/FAQ.php?s=probs&display=throttlehang

A sticking IAC valve, and cleaning thereof, is mentioned here:

http://www.contour.org/FAQ/FAQ.php?s=probs&display=highidle

98 Mystique LS v6 atx 163,000km 97 Contour LX v6 atx 163,000km