You might have some luck cleaning the O2 sensor. I just cleaned mine after getting a 2-1-2 code a few times. Here's what I did:
1. Put car on ramps.
2. Use 7/8" wrench to unscrew sensor from underneath car (the sensor is in the exaust pipe just before the caltalytic converter).
3. Use wire brush to scrub off the carbon soot from the sensor.
4. Heat ceramic end of sensor until cherry red for a couple of minutes.
5. Allow to cool a few minutes and then spray with brake cleaner.
6. When dry, brush again and reinstall sensor.
7. Clear codes & drive happily away.

BTW, my car is a '94 855 na. Your setup may be different.

Good luck,
Rick in West TN