I used an obdII scanner because my check engine light came on. It said there was an issue with the Bank 1 Sensor 1 O2 sensor. I saw a few things online that the O2 sensor might still be fine but I decided to replace it anyway. I cleared the code right after installing the new sensor and the same error came back later that day. Someone please help!!!

 

Do you have an exhaust leak? Any aftermarket performance parts/bolt-ons? Sometimes you may just need to drive the Z for a bit for the "self-test" to complete, 10 minutes of driving or 20 miles is probably not enough. You may need to drive 200 miles through all kinds of driving conditions for the code to clear with the new sensor installed. If it still won't clear, then you may have another issue upstream or downstream in the exhaust system. Potential problems with the OEM cats for example, or perhaps the engine is running too rich or lean. You may need an experienced mechanic who can check live data to narrow down the root cause.

For the time being, I would recommend searching this forum with the code you're seeing. More often than not, other people have had this issue and sometimes the initial code being thrown is a reaction by the car's computer to a completely different but related fault.
-Icer

 

It has an intake and exhaust. I can smell gas at a red light so I think it’s running rich but I thought the o2 sensor would fix that. The sensor is located on the exhaust manifold so I don’t think there is a problem with the aftermarket exhaust but maybe the intake??

 

Well an O2 sensor won't help you if you are running rich, it will only tell you you are running rich. Is the intake new by chance?

 

True, usually a bad O2 sensor will cause changes with the fuel maps, most people report terrible fuel economy and power output issues. Was the gas smell there before the code for the O2 sensor was thrown?

Which intake are you using? I would start by checking all the hoses connecting into your intake manifold. Make sure you don't have a vacuum leak somewhere. Also check your air filter, if it's a CAI system with a pod filter tucked behind the bumper, make sure it isn't clogged up with road debris. You could try cleaning your MAF sensor as well, but be warned that this can sometimes make things worse. Only use MAF cleaner products (no brake clean, etc), make sure your battery is disconnected before touching the MAF sensor, make sure it fully dries out before re-installing.
-Icer

 

I have an injen intake and it was located behind bumper but I decided to move it up to the engine bay, so it probably needs a good cleaning. I will start with cleaning that and the maf sensor and hope I don’t have a vacuum leak. Thank you!