okay, i think I may have my header and o2 sensor problem fixed... I hope anyway. When I went ot autozonr they sold me a bosch #15710 oxygen sensor. I went to bosch web site and the website says the part number is 13929 for the bosch primary sensor. The 15710 plugged right in, but i am hoping it is in fact the wrong one. Does anyone know the part number of the oxygen sensor for a 1998 honda civic ex?? Or am i still out of luck with the check engine light coming on all the time?