do they turn your check engine light on.

can i put my o2 sensor in them?

i might buy some from someone i know their discontinued.

Isn't the O2 sensor on the S-Pipe?

on the header also. you just need the antifouler on the spipe

i thought the header is a A/F sensor?

^ you are correct, the sensor on the header and the sensor on the s-pipe are not the same thing.

05 TRD is right....
A/F sensor on the header, and o2 is on the s-pipe

my bad, anyway will it come on and how do i fix it?

antifouler for the 02 sensor on the s-pipe. The header A/F sensor can be directly connected to the header.

my stock A/F sensor ?

search for anitfouler

thanks, just to clarify ill use to anitfouler for the s pipe and my stock A/F sensor on the header?

yes

The tC i just bought has the same problem. it has a header put on and the check engine light is on. i heard that headers damage the engine or the catolitic converter. is that true?