Check your IAC(Idle Air Control) valve. it sticks, and causes a loss of air at idle (not enough to keep it idling...)
On the ZETEC, the engine will be slightly different, but it will still be next to the throttle body, and air tubes.. and will look like the same part.
Look on the FAQ thread (under ZETEC maintenance, or perhaps on the MAIN page of contour.org (under FAQ, then Common Problems) for a how-to of removal and cleaning/replacing it..)
Ray
