i have the same problem with my 1600 zetec escort! changed coil, plugs, leads, MAF, and even checked the cat! after some tips from pf and a quick call to a local ford specialist, all signs lead to a faulty lambda! when the lambda goes down it messes with the air to fuel mixture and drops the voltage at the injectors, thus causing lack of power. got a sensor off ebay for £15. well worth a try before spending mega money on diagnostics!!!