OK, so I have been putting it off for a while but I did it today. I assume that the method used here at H-T for checking CEL lights only shows 1 error at a time. Well, the first error I got was 1 O2A - Oxygen sensor #1. OK, cool, that's fine and easy to fix. So I then go look at my engine which is a 99 B16A2 with the P2T SI ECU and Type R header. I look at it and I can't seem to find the O2 sensor. Now I assume it is a Type r header because it's a 4-1 design with the mounting brackets for the heat shields, am I right? Anyway, so I jack up the car a little, but I can't do it a lot because of a rocky surface and doesn't seem safe. I look underneath the car, still can't see an O2 sensor or even any wires. Am I missing something? Is the O2 sensor on top of the 4-1 collector and I just can't see it? Anything for help.