well i replaced the OEM cat with a high flow and now im getting a constant cel. i cleared out the codes a few times and it will stay off until i get around 7 k. dealer wont do anything about it (voided the warrenty so they tell me) the 02 sensor is stuck in the lean position. which in my mind means the ecu is compensating by dumping more fuel and im running slightly rich. this has been happening for about a week. the newest code i have now is "engine running rich" dont have the actual code number ill get it posted soon, in contrast i also have a "engine running lean" - WTF..... does this make any sense to any of you? i have an obd2 scanner, and i have started storing it in the glove box, this is really getting to me.

mods- custom intake, straight pipe single outlet exaust.

also can i just remove/ relocate to o2 sensor that is at fault to a more reasonable location for my setup? id like to think i can bypass it with some crazy wiring setup and a small circuit board ( that i make at work)

 

Is the upstream o2 still there? It is the one that sets the injector pulse width. The downstream only checks catalyst efficency

 

yes according to the code its the upstream sensor

 

Did you reinstall it? You might have damaged it or the connector with you removed it from the cat. Without it working properly you can have lean or rich or both codes. The PCM doesnt know how to properly set the injector pulse width.