I searched but couldn't find an answer to my exact situation. Anyways, is it ok for me to take a spin around the block without an O2 sensor? I just did my timing belts, full transmission swap to LSD, clutch and all and I have to verify that the transmission works. I'm missing my header collector bc I sent it to Hytech for repair so I just connected it with aluminum sheeting. My set up is fully tuned on S300. It's an n/a H22 with fully built head but I didn't wanna take any chances. Obviously I'd rather take the chance in missing out on my warranty for a $1,000 transmission rather than mess up my motor some how. Thanks in advance.

 

I'd be more worried about driving around with no header collector than no oxygen sensor but no, it won't ruin anything. The car will just run in open loop (which it has more thn likely been tuned to run in anyway)