Joe S and Beetlejuice,
As a neutral observer in this discussion, let me put my 2 cents in and try to help.
I think this discussion centers around different definitions of the term "coking".
The first time I heard it, years ago, was in the time before water-cooled turbos, where the oil in the turbo would (when the engine was shut down with a very hot turbo) cook or turn to coke (carbon) in the turbo from the extreme heat. This solid coke would impede the cooling and lubricating oil flow to the turbo, further reducing the flow and result in a clogged or coked up turbo. The term coked up then was used by many to refer to any blocked oil flow.
In the case of the variable valve timing solenoids, there is nowhere near the type of heat to burn (coke) the oil. Those sticky solenoids are caused by an admitted factory manufacturing defect, whereby machining particles were left in the solenoids. There is a TSB on how to clean out the older ones which can be disassembled. I've replaced clogged ones with new ones which soon failed due to this defect. I think that by now the new ones are shipping clean.
I hope this helps and is the nut of the discussion and you two helpful guys can put this behind you.
Thanks for listening, Larry P.