Check Engine Light (CEL) came on. I went to Autozone and had the codes read. P0507 and P0141 came up. I bought the Bosch OEM replacement for the secondary sensor that screws into the catalytic converter. The wire from the oxygen sensor comes up through the floor board under the right front seat and plugs into an OEM connector. Be sure to replace the oxygen sensor with an OEM version, so you can easily plug it in without cutting any wires, etc.
Check Engine light came on,Would not smog correctly. Changed O2 sensor. Not the problem. The O2 sensor was not getting a charge. Ray at Shell figured out it was a relay switch. Check Engine light went off. Relay switch was 10 bucks.