New to group, love it so far, hope you all can help. I have a 2000 Yukon Denali 5.7l. It was initially showing tc po0420 and po0430 which i believe are catalyst insuf problems, 2 days agao when driving highway speeds the truck started losing power and sounds like it is choking out, when I turned off and restarted it ran better but still had a lot of missing noted. I changed to eternal fuel filter, plugs and wires yesterday. I thought it was better but after about 60 miles it started having the same problem. Now it it is showing tc po131 (HO2S bank 1 low voltage) would the O2 sensors cause the truck to loose that much power and stutter or am I chasing 2 different problems. Any ideas wold be appreciated. Thanks