I am currently having same problem with my 08 Fiesta 1.25 Petrol. It is usually not long after starting journey when car has been cold. Powertrain warning light flashes and car starts revving. Engine management light is on either red or yellow and screen displays 'Please Check Owners Guide Engine System Fault'. This continues until you switch off, wait a few minutes and start engine again. However, sometimes after a few minutes of driving, it does exactly the same thing again. Not ideal when traffic light has just turned green!
I have taken in to Ford garage who said a fault was showing, they cleared it and took car for a drive - no fault reappeared so I was charged the time and sent on my way with "There's nothing wrong". Taking car back tomorrow and leaving it there until they fix it as problem is becoming much more frequent.
Kathryn
November 2014