You're right, I have several definitions, but as you mentioned earlier, they are open to interpretation, (i.e. it could be the sensor, or it could be something else causing the sensor to read lean). That's one reason why I wanted the offical Ford definition of the code. I hoped that I might get more information from that source. Anyway, I have replaced the o2 sensor and the egr valve. The egr was original with 127K and the o2 had about 60K. It was time for replacement, and the car runs well with no cel yet. Thanks for your help.
