Wattup .. im new here but check this out. I put a 4-2-1 header in my 96 civic and the old O2 Sensors were rusted into the exhaust manifold so i left them in and threw it away. I bought a new one (only one) to see if i can work around the check engine light since i dont have a cat converter. i can see the O2 sensor detecting the amout of oxygen in the exhaust before and after the cat, but since i dont have a cat can i get away with only one? Thanks. And i will have pics up soon under the 4-door. Thanks again. Please email at [email protected].