Hi- I started asking about this in a 911 thread about a guy with a 6.0L with the same problem, and I'm moving it to the 6.4 only forum.
08 6.4L 4x4 CC 5200miles, 6" PC lift, 35's, etc. Just got it in June
Turning out of the neighborhood, don't hammer on it as it early, engine isnt fully...