Hello, the o2 sensor have no activity because they are full rich or lean. Check the air intake boot for leak, check for vacuum leaks, check the fuel pressure regulator vacuum line for fuel, if any leaks are found replace or repair as needed. The original 02 sensor were probably ok. The additional codes could be from the new sensors. Please check it out and get back to me.
Tuesday, April 8th, 2008 AT 6:34 PM