Hight Elevation Error Codes (P0131, P0151) at 7K+ feet

[privateer]

High Elevation Error Codes (P0131, P0151) at 7K+ feet - 5.7L 350 Vortec.

1996 Tahoe, 5.7L 350 Vortec.

I'm getting O2 sensor P0131, and P0151 error codes when driving up mtn. passes. The error appears soon as I get close to 7000 ft. It happens from anywhere between 2500 rpm to 4000 rpm. On a consistent level. Soon as I clear it, it reappears.

I've replaced the O2 sensors a few years back, is it possible these have gone bad already? Or is there another issue causing the sensor codes?

I'm not getting any errors at lower elevations, just when driving 7000+ feet.

Any feedback is appreciated.

Thanks

 

[SunlitComet]

If good delphi or delco sensors they should be okay but i might add the you should probably have you map sensor tested for full range of readings. If both banks are popping up i would think the map sensor is no compensating for the altitude change. when it it comes on again on high altitude. Shut down and restart that causes the map to remeasure barometric reading before engine is running.