Just thought I would post this here to help someone else out if you run into this. My 460 truck failed with high CO on the high-speed test, limit is 1.2 and I was at 2.2. High CO is caused by a rich mixture, so I replaced the O2 sensor just because I had one in my toolbox already. The CO dropped to 0.04, just got my sticker at lunchtime today.

 

Great feedback, thanks!

 

Always an upper when you pass through smog check!
Roger