I have come to the conclusion that the RECIRC vacuum line has a leak in it. Based upon my observations, the "default" position is RECIRCULATE mode... IE the flaps close when the climate control is switched off. THey open on the freeway.... when I have the CC on economy and fresh air, air BLOWS (very fast) through the vents... and when I push RECIRCULATE, the airflow slows down to normal.

Air is forced in through ducts (below windshield, forcing open flaps....? Must be a leak I suppose... seems like a pretty sure thing...
Would a fault code appear if so? (I have 28, 60, 80, 82... all "intermittent" vs "continuous" codes.)

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)