0138/0141 code.....

[lleno65]

My truck kept putting the 0138/0141 code out.so I replaced the downstream sensor[sensor 2],but it is still putting it out.I had cyl 1/2 misfire codes also,which I was able to clear up[new plugs].I'm pretty sure I have to replace my plenum gasket,I have disappearing oil,about a qt every 250 miles..I was reading this can clog the o2 sensors?? Any advice appreciated....Leo

 

[Saabonthis]

I would start with replacing the plenum gasket. That could be the cause of your codes. I'm in the process of doing mine. Highly recommend the updated plenum fix from Hughes.