Have you checked the plugs to see if you're getting a weak spark? If so then I'd look at swapping the coilpack over for one from a scrappy (any EDIS equipped CVH Ford will have one at the scrappy - they should cost £10 or less). Once changed and you find it's still giving a weak spark then I'd say check the CPS and after that look into something around the ECU/Chip/Fuel pump side of things.

Cheers,

Andy