If it's idling better with the check engine light on then maybe the mass air flow sensor is going faulty? just a guess, but when the light is on, it's using mapped values and not sensor inputs. I do know for a fact a bad mass airflow can throw O2 sensor codes. Too lean AND too rich from the same sensor or all sensors usually points to this. A buddies Thunderbird was doing this and running terrible, we unplugged the Mass and it ran fine until he could afford the $150 to buy a new one.

-Todd
1987 Montero 2.6l 5-speed (Sold...but I still miss her)
2008 Jeep Patriot Sport 4x4