OK... After reading it again, I know what it's trying to tell me. The second cat is not doing it's job, or the O2 sensor is going out.

At this time, given it's history of carbon issues, I'd say the cat is clogged. But where'd the carbon come from? I'd say it's possible it came from valve guides. It's a streatch to say it's the rings, but I guess it could be.

Short version, it's burning oil. It could be oil from the EGR system, or valves, or maybe even rings.

What I don't know is if fuel injector cleaner could do it.

"Stubig" - '72 416.141 (U1100) Unimog
"Sassy" - '05 KLR650
"Brody" - '04 Rodeo (It's my wife's, really)
"Candy" - '02 TDI New Beetle (yes, a family of 4 fits inside)
"Twinkie" - '72 Revcon 250 (converting from Olds 455 to 6.5L Diesel)