If you have had scanner attached and only has code for that sensor then should be inspected and repaired. It can cause cat conv probs. No explanation about why you feel the performance went up. What do you mean by that?
Hills that I use to downshift to 4th, I can stay in 5th with pedal to spare. Pick-up has also improved. Haven't noticed any change in fuel consumption. Can I remove CAT conv.? County I live in has no emissions inspection. Appreciate the reply. Thank you.