Hi just knew to this and looking for some help.
My Ford Fiesta 2007 reg started shuddering last week and engine management light came on at 2000rpm. Took it to a garage straight away who said i needed a new coil pack. Fitted that and drove out the garage and light came back on again. Took it back and got spark plugs replaced and everything was fine, no light on. However its now slightly shuddering when idle. Don't think it's doing it when its driving, well i haven't noticed. Any ideas what the problem could be now? Someone had mentioned the idle valve maybe?