O2 Sensor Error, Banks 1 & 2, Sensor 2

[crypto]

My 2002 silverado 1500 has about 135,000 miles on it and is still a nice tight truck. It is a 5.3 w/ auto, non-california, built in Canada. I got an error saying that my bank 1 and bank 2 #2 sensors (after the cat) were faulty. This first happened while crawling (almost idle) through the forest in low range at 8500' above sea level. I assumed some sticks may have tore some wiring but was unable to find any damaged wiring. I thought it was odd to have both sensors go at the same time, but I bit the bullet and bought two sensors and replaced them and cleared the code. After a couple days and about 50 miles the error returned while sitting idle with a warm engine.

The truck seems to be running fine, idles smooth.

 

Other than cleaning the intake system and injectors, I do not know what to do at this point. I assume that cleaning isn't going to help anything since it is the sensors after the cat converter.