I removed mine, and replaced with a cat-converter lookalike. It still gets the job done, but there is a Engine Check light that always comes up from the sensor. According to the foreman, temperature is not high enough hence it is sending out fault codes. Is this something that I can fix or I will have to live with it due to the decat?
Have u covered the exhaust part of the post cat o2 sensor probe? Have a look at this thread: http://forum.e46fanatics.com/showthread.php?t=486937&highlight=spark+plug+non-fouler