This is a word of warning for focus drivers on spark plugs and water !
Today i had the RAC recover my car. Water from the washer jets was leaking into the engine and finding its way into the spark plug ports. It caused a short circuit damaging the coil and plugs !!!!
To check this pull out HT leads and make sure that inside ports is dry and no "rusty water".
If their is i would suggest removing and replacing plugs and draining water out !!!
Also new modified washer jets with better seals are available from ford on part number - 1501053 cost approx £10 per washer jet.
i hope this helps someone and will prevent costly repair and recovery !!!!!!!!!!!!!