I found the link to find out if the engine is good or not:
Its a google document that has instructions on how to pull codes from an older toyota engine. But it also has information on how to test whether the oxygen sensor is giving a true reading or not.
The information is listed near the end of the PDF, look for this title:
USING VF TERMINAL AS A CLOSED LOOP AND A/F RATIO MONITOR and follow the instructions there.