Error code 41 and 43 on 1990 Accord EX

Hi All:
Check engine light went on. Read the error codes, the are 41 and 43. It looks like the O2 sensor is bad. Can it be anything else? Did anyone have a happy end whith a O2 replacement sensor? What else should I pay attention to when replacing the sensor?
Thank you in advance!

Expect to pay $60 for a Bosch OEM or $75 for a Bosch Universal...

It could be many things but most likely it is the O2 sensor. Other things could be connectors, wiring or the ECU. The 43 code could be O2 sensor or fuel supply problems.