FYI - please refer to the below topic regarding more info/possible solution to engine idle problem (misfire).
http://www.fordforums.com.au/showthread.php?t=16161
It's easy to check, just make sure it's dark enough to see a blue spark and be sure to keep the air box connected (just swing it around and rest it on a rag on top of the coolant resevoir/fender - upside down!) because I had to let the car reach operating temperature before it started tracking.
The spark/tracking should correspond to the sound of the rough idle. I would take a photo, but it's just too dark lol.
Good Luck!
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