those...uh..o2 sensors suck. Very sensitive. The guy at autozone yelled at me for touching the end with my finger. They are made to measure miniscule amounts of gas, and the slightest contamination can throw them out of spec. A new o2 sensor will work a lot better, and the bosche ones carry a lifetime warranty. they are only $60, but the real pain in the...uh...arm....is getting the original sensor out.
Read about my adventures while trying to change the bank 2 upstream
