I've had this on mine, seems to just drop in power for a second, usually whenacceleratingaround the 2000 rev range.Today I was driving home when the dreaded red light came on with 'Engine System Fault' on the display.AA came out and his diagnostic computer brought up

1101P1757P0101P0299P0562
The gist of these were 'low voltage', 'something to do with airflow', 'something to do with the turbo pressure' and ,something to do with the throttle position being misaligned with what the sensor was recording. (sorry for the vagueness)
Anyway he reset the codes and they cleared, so I went on my way home. It came back on for a minute but cleared again. Need to give Ford a call on Monday.
Recently the exhaust sounds to be blowing/leaking somewhere too if you ask me.
Anyway some of the things mentioned here (turbo/air filter/loss of power/throttle) are consistent with my problem so thought I'd add my 2p worth.