[DW SD]

After discussion with Grady, seems like somewhere the system is bleeding off pressure and that is only noticeable at idle conditions.

* Can a faulty cam oil restrictor drop the oil pressure only at idle (by letting full oil flow to the cams)? I don't know how these mechanisms work. I'm assuming it is just a restrictive port or "jet" to reduce flow, which probably doesn't break, but that's only my guess.

* Is there another location at which I may test oil pressure to narrow the focus of the pressure drop? (In other words, once this is taken apart, is there an area of the oil system on which to focus our attention)?

*Can this be an issue with the pump itself?

some more data:
* Oil pressure is 2.5 to 3 bar at 1200 rpm @ idle upon cold startup (ambient is about 70 degrees in the morning in San Diego, currently).

* Around 180 to 190 degrees, the pressure reduces to the point of turning on the idiot oil pressure light.

* At >2.5k rpm, the gauge is pegged at 5.5 bar, cold.