CCV (cold version)
Did you (are you) replacing the CCV Oil separator with the cold climate version?
I dont have any evidence of gunk in the old tubes, but am going with the 'cold' version anyway as I'm likely going to end up in the Dallas area for a while. Most of my miles were highway (100+) miles per lap.
The 'cold' version is a joke. An ill-fitting rubber coating (that I used a sealing tape to bind the halves together!) I think insulated something would be just as good - of course getting it to fit back onto the plenum might be another story.