2005 Infiniti G35 M/T Tuned
MODs: Plenum Spacer, 75mm TB, 3.5in Intake, Motordyne MREV2 Manifold, Test Pipes, Z1 Y-pipe, Soho cat-back, and Oil Catch can

My G35 is pulling code p0057 which is for a O2 sensor. As of right now, while idling the rpms drop like it wants to stall out and then jumps back to normal rpms. it does this the whole time while its idling. While driving the car sounds like its stuttering and the tone of the car is like a loud vibration. I havn't switched out the O2 yet because I read somewhere that when you get a tune, the o2 sensors that are downstream are disabled. So what do you guys recommend? What should I do first? Ill still end up switching out the o2 just to see if it fixes anything. I also read that adding extensions to the o2 could also work but what do you guys think. Ill upload video link but they aren't the best. You can hear from the tone of the engine in the video that it ain't running right.

Video 1 - https://www.kapwing.com/videos/6535431d749c62ce29ff6206
Video 2 - https://www.kapwing.com/videos/653543c957792c06b5f69af6

 

Same with me. bank 2 sensor 2 . you figure it out?

 

Do you have any modifications? Sensor 2 is downstream, if you have exhaust modifications that could be causing it. Depending on if you have to pass emissions testing or not a tune might be able to fix it