So i bought a 2003 350z vq35d3 3 weeks ago, wasn't in the best condition, the miles showed 143000 miles but ac module was home so no telling how many miles. Only mods i can see is a k&n typhoon intake, missing the lower ram intake so just has the pipe and air filter, pic is included, and magnaflow exhaust. I've removed the ac belt due to the compressor making noises. I've replaced spark plugs, changed oil change replaced both cam position sensors, cleaned throttle body and replaced gasket, and yesterday replaced bank 1 sensor 2 to hopefully knock out the cel light, but this morning on my way to work i got a mile from home and cel light came back on for the same thing, p0037 i think, the old o2 was coated in carbon as in picture. The plug for the sensor coming from the harness is missing the clip part so i couldn't tell which way to plug it in but there was only 2 ways, could i have plugged it in wrong?? The fuse is still good, could the cat be bad?? I have z1 test pipes I've been looking at. I'm new to the mechanic world but I'm a quick learner and i love nissan, the 240 was my original goal but came across this headache and decided to tackle it, but any help would be greatly appreciated.

 

Is your new O2 sensor OE or aftermarket?

 

It was a Bosch direct fit