2004 Itasca Suncruiser W22 - P0131, and p0135 going over Monteagle on I-24

[rsieminski]

So we got the p0131 code, just over the peak of the incline on E I-24 in Monteagle, limp mode, no engine light?? I pulled over, cleared the code, and never got it again.... UNTIL we crossed back over coming home. Again, just after the peak, limp mode, no engine light. Pulled over, cleared p0135, and never got it again all the way to W. Central, Fl.

Engine temps were normal, and up the mountain, we were going about 50-55mph. I looked up the elevation, and it's only about 2000 ft. Should I just replace the O2 sensor? I have been unable to find an exact PN for this, are there just generic ones that pop in?
Thanks!!