If it wernt bad enough my van playing up this week my mrs car has developed a small problem.

It's a 2007 focus cc with a 2.0 duratec.

Starts & runs perfect but every now & then will develop a slight misfire & hold back.

I plugged it into a mates Bosch kts200 & it showed no faults, next day it was ok but called out the AA & again found nothing.

My first thoughts was a coil pack or injector but not sure if that would cause an intermitant problem?

Any ideas?