1997 taurus code 0430 is on means catalyst system efficiency below threshold bank 2. the light goes out on own after the weather warms up and car is driven for awhile. it has had lots of idling due to cold weather. is it a clogged catalytic converter or a faulty 02 sensor?
Verify the front and rear o2 sensors are responsive. If so, have a muffler shop test the cats.