[CSI KY]

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

 

[silveradotrailblazer]

If its the rear O2 sensor you could have a bad cat (plugged up) so that would explain the loss of power.

 

[jbjohnson92f]

welcome to the club, sounds like a plugged cat to me as well

 

[CSI KY]

Thank you for the replies. After much troubleshooting I changed the fuel pump and the problem and trouble codes have ceased.

 

[silveradotrailblazer]

Glad you got fixed. Also welcome to the club.