Your lambda reading of 1.04 suggests a slightly lean mixture, yet, you have 0.7 % of CO, saying slightly rich.
Could be a lazy ( on it's way out ) O2 sensor.
Ckeck- in on another topic here ( by " 95e320" ), in which Arthur Dalton gives a very brief, but practical hint on how to determine the activity, or lack of, an O2 sesnsor.
