Arturo Bencosme

hello everyone, ive bought a pair of long tube headers for my GS and noticed that they only bring 1 bung each for the o2 sensors. the stock ones bring an upper and a lower. can someone enlighten me on what to do here?

cam1969

The sensor before the cat (between cat and engine) controls the air/fuel mixture, the one after the cat is just to check that your cat is still functioning. Most people who run headers don't run a cat so they don't use the downstream sensor. They have their PCM tuner remove the fault code. If you do run a cat after your header, you will need an extension harness to get the second sensor to reach.

russ472

to add to this, the 2nd o2 sensor bung will be made into the xpipe that comes with your headers