Ford Focus 2L petrol zetec misfire ?

[ZR1cliff]

My little runaround has been problem free until today, when I noticed a misfire underload. Later the engine management light came on and when I rev the engine in neutral it is also missing. It's as above a petrol Zetec.

Coincidently today was the first time I brimmed the fuel tank in the four months I've owned the car and wondering if this has anything to do with disturbing any loose debri in the tank ? I've been on a 300 mile round trip today.

[ZR1cliff]

It's a 2002 by the way.

[Zetec-S]

Can you get anything off the OBD? If not, then:

Spark plugs/ignition leads?
Coil pack?
Fuel Filter?
MAF sensor?

Probably in that order. I know coil packs are a fairly common issue with those engines, but should be cheap to fix if that's the issue.

[Poynter87]

I would try the coil pack first, as this has been the cause of a misfire twice on my mk1 focus rs underload, then I would try the leads and plugs.