Here the link to my original post and write up on ebof
http://www.ecoboostownerforums.com/forum/ecoboost-taurus-sho-mks-forum/ecoboost-sho-mks-maintenance-troubleshooting/1931-need-help-troubleshooting
And here is my last post after it was fixed.
" Pulsing Vibration finally fixed
07-04-2013, 03:02 PM
It's been kind of a nightmare dealing with this problem. But it's finally fixed. It ended up being the RDU. Here's a list of the parts ford already replaced before the RDU 1 wheel Entire driveshaft assembly All four wheel/hub bearings PTU assembly AWD control module RDU Total time for all repairs, troubleshooting, waiting for parts. ford had my car for 8 weeks!!! The RDU is built by ZF to order, so they do not have them in stock waiting for shipment. Oh and I replaced all 4 michelin tires with new michelin mxm4. Michelin gave me a 50% credit on 3 of them. So if you have a pulsing vibration above 50mph ...........IT'S THE RDU!!!!!"