So i got headers for my ST almost a month ago, and the second o2 sensor has just been dangling because I never bothered to put in a bung.
So yesterday, I was driving and my check engine light came on (I was driving like a d*** with my friend ), anyhow nothing really seemed to be affected, and I drove to the gas station and home fine.
So when I was looking for anything obvious, I found my o2 sensor sitting kind of inside the rear engine mount... pulled it out and it was smooshed! (assuming it got stuck in there, and the engine tweaked a little when I was driving not so cautiously-

Anyway I disconnected my batteries, and plugged in the o2 sensor I originally bought to screw into the downpipe's o2 bung that I never bothered doing.
Started it up, and the light is gone. I reset my air/fuel ratio after that (followed the steps in the how-to section)
At idle it runs alot better now too

Just wondering if a smooshed o2 sensor would throw a code? thanks

>
Not having that sensor is probably what pulled the code. I left my secondary one off and every now and then after long drives I'll pull a code when i accelerate too fast. I check it anyhow, and pull the same code (27?)....In fact it just happened to me this past weekend. BTW, you should of never left that secondary O2 sensor just dangling there. At least unplug it and remove it.

oh you can just unplug it? I just thought that would pull a code automatically, but thats cool, I'll unplug my new one tomorrow and send it back get my $40 back lol
When you pull a code, does it affect your cars performance? When mine did it, it didnt feel any different, just the light was on-

I cant say it does one way or the other. But yeah, I unplugged mine when I took it out, as the sensor was seized up in there and whatnot.

alright, well thanks for the info, i'll test it out in the morning

get a bung welded into the exhaust and and use the anti-fouler with the O2 sensor to keep the check engine light off.