For a couple months I've been getting an engine light off and on for P0420. It will come on and stay on for about 3 days and then go away and stay way for about 3 days--intermittent in other words.
So I've been waiting to take it in to have more diagnostics done besides just knowing it's bank 2 cat con related. Then several days ago I exited the highway up a ramp and came to a stop. When I pushed on the accelerator I was shocked to see a plume of blue/gray smoke issue from the passenger side exhaust.
Since then the engine light hasn't tripped again, and I'm wondering whether some kind of constriction was cleared that was causing the code to trip intermittently. It has run smoothly through all these episodes. Any thoughts?

 

The engine draws air through the crankcase via the PCV (LHS top of engine) and

into the engine side of the TB.

If you drive your car gently over a long period,oil builds up in the pipe work

and PCV, when you floor it, this oil is sucked into the engine.

Clouds of smoke-very worrying but I bet if you floor it again you will not get

the smoke.

I never had the engine light.

I don't know if those corrugated plastic pipes are the same on the inside but

what an ideal way to trap oil!