O2 Sensor?

[Maarek]

Well I was driving the other day, Everythin was all fine and then after maybe 30 mins of driving Service light turns on and I start to get bad idle problems, The car drives pretty normally just idle and maybe when you start the car you have to give it a tiny bit of car to get it to catch. I went out yesterday and pulled codes and I got #11 O2 sensor, My A/F guage goes all the way full on partial throttle driving. I had just replaced the O2 Sensor not 1k miles ago but I decided to replace it again, Well I just took it for a 20 min drive and nothing changed, gave it some gas and thats when I found I needed to give a little bit of gas to get it back up and going. =\ So I am not sure whats wrong..? I went through an ECU not too long back and replaced it with another used one from a 1g turbo. Maybe another ECU going bad? anything I can check for to isolate the problem? I have a MAFT which I had tuned but as I was saying everything was driving fine untill just a couple days ago when I got the service light. Thanks for the help.

 

[Maarek]

I have heard that it can take some time for the ECU to relearn the curves after I reset it. Would it still run rich like it is now? I am going to drive it around tommarow for a while to see if I can get it to show signs of something different but if that doesnt work what should I be looking for??