Originally Posted by JinTae

I didn't read the entire thread so hopefully I get most of this correct since I just skimmed through everyone's responses. I have an 04 1.8 S and my friend with an 03 gxe installed our hotshot headers together. First off I don't know what the guy that started this thread is talking about when he says he put 2 o2 sensors into the hotshot header. The 03-06 QG18DEs have one top o2 sensor and one bottom o2 sensor. The bottom o2 sensor should be plugged into your exhaust's o2 bung and the top o2 sensor should be plugged into one of the o2 bungs on the hotshot header. 00-02 QG18DEs came with 4 o2 sensor total I believe (2 up to and 2 downlow...not sure since I don't know anyone with a 00-02 QG so haven't been able to see it myself but this is what I hear) and a EGR. 03-06 QG18DEs do not have a EGR sensor so just plug that hole. Also plug the other o2 sensor bung since you'll only be using one of the 2 available o2 sensor bungs. My o2 sensor is currently in the EGR bung but I'm planning on moving it to the o2 sensor bung that is inbetween the EGR bung and the lower o2 bung. According to some people on b15sentra.net they believe this is the best spot for it so I decided I might as well try it out. Anyways for sure you will throw a SES light. If you don't want to have your Service Engine Soon light on and you own a 03-06 QG18DE then don't put on the header. For all 03-06 QG18DE we're pretty much screwed until someone designes a new header for us. The code my car is throwing is P1279 which is Manufacturer Control Fuel Air Metering. I believe this is basically my top o2 sensor telling me that my air fuel ratio is off since the o2 sensor is now only reading one of the header pipes because the hotshot header is retarded for the 03-06s. Anyways, I'm assuming that if I pick up an Apexi SAFC-II and I tune the air/fuel ratio correctly with a dyno then I should be able to get rid of the SES light since I'll have corrected the air/fuel ratio with the SAFC but that's all a theory for now. My friend with the 03 agrees with my theory but until I try it out I guess I won't really know. I'm not sure if any of this helps but hopefully it does. I guess if you guys have any questions you can feel free to reply here or contact me.