this happen to my 09 at 20,000 miles+
I would be driving on the freeway at 65mph and then all of a sudden my car would turn itself off!!
i would have to put it in "N" and start it up again
(AFTER HAVING TO RESTART THE CAR 4or5 TIMES THE CHECK ENGINE LIGHT CAME ON)
my dad a techni brought home his scan tool... scanned the comp
and it told him the code in which the TB was failing.
After that we took off the stock intake and looked into the TB
it was dirty< we cleaned it and put it back together...
later it happened again and again till it thru that code... and he said I'd have to take the the Dealership replace it under warranty..
^so they did and i got a new TB <the problem never CAME BACK..
sorry to hear that another FOcus is acting up AGAIN.