Car completely shuts down without warning. Will start right up as if nothing happened.

I'd focus on the Camshaft Position Sensor and the Crankshaft Position Sensor. Go with BWD components, with a lifetime warranty, if you decide to replace them. Also, ensure the platinum spark plugs have been replaced, if they have not been changed in 50,000 miles (Motorcraft only).

Try car complaints.com:
www.carcomplaints.com/Ford/Taurus/2006


2006 ford taurus problems - Google Search (http://www.google.com/search?q=2006+ford+taurus+problems&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1)

Also do a Google search for "2006 Ford Taurus recall"

Check for any hard and soft codes.