My car has problems ( Possibly Major )

[the_dubmeister]

I was driving my car along to work yesterday afternoon, i went to put my foot down a little to overtake, and the normal kick you get from the turbo just was'nt there in the slightest, i slowed down and then next minute all the car is doing now is juddering all the time, and sounds like its misfireing, i'm wondering if any of you could point me in the right direction as to what it is, a friend of mine said it could be a coil pack whats gone, or it could have even melted a spark plug, but then there's no rattle in the engine, the entire car just feels like its got about 40bhp and is misfireing, giving it that juddering feel, any ideas would be appreciated.