Oh and by the way this should help!

A:New 02 sensor
B:Oil Fouled 02 sensor
D&E: Carbon Fouled and normal wear 02 sensor

 

Thanks fro the great info! My rear sensor is definitely B and then some. I guess I'll try buying a new one and slip it in. Can I use the same one for the front if it isn't the rear that's the problem? I'll be out of town until wednesday so I won't be able to try until then.

 

Most likely due to the plenum gasket being blown and letting oil into the system. I'd look into getting that fixed soon, IMO.

 

Yes the 02 sensors are interchangeable.....and second to jasonw on looking into your leaking plenum issue, oil in the exhaust is more then likely a leaky plenum gasket on Dodges!