just to check. does it sound like a miss fire being all stuttery or is it more like the engine is being labourd way too much? if the latter then throttle possition sensor is a likely cause especially ifshe runs sweet the rest of the time.

the sensors themselves arent expensive from what i can remember. easy to fit too although may be worth disconecting the battery for 1/2 hour to reset the ecu to its base settings. actually might be worth trying that first anyway just in case its got itself in a knott so to speak.