MOBS
The Mad Scientist
If you ever remove your intake, it wouldn't hurt to plug the egr port where the intake and head meet. If you look at an overhaul/rebuild kit(or simply an intake gasket kit), it will have little tin-foil looking plates/plugs that fit inside the intake side of the egr port, it blocks the hot exhaust gasses from rising into the intake during idle and low rpm. The heat from the gasses can cause the oil fumes in the oil galley to bake to the bottom of the intake and over time, it can cause cracks to appear in the bottom of the intake manifold, causing it to suck in oil/fumes(especially at idle) and cause a light smoke. This is most often seen on service vehicles where they're idled alot.