It's likely to be an ignition problem. When you accelerate, the petrol-air mixture is richer, and you need a bigger voltage across the spark plugs to get a spark. This can cause a high voltage short circuit across the ignition leads and misfiring. Try drenching the ignition leads and distributor with WD 40 spray. If there's still no joy try changing the spark plugs. The spark plugs are difficult to remove from the Duratec-engined KAs and you might want a garage to do it for you.