misfires

Hello, I have some serious problem last few weeks and its actually getting worse. It happens especially when engine is still cold. When i put my foot down it misfires (terrible loss of power - feels almost liek ESP kicks in with a big bang from exhaust). When i put gas pedal only half way...

My car is missfiring/spluttering under load on full boost. All pipework seems ok, coilpacks all seem in order as it runs fine until full boost and no engine lights. Vagcom also hasnt detected anything. Tried a new MAF and my spark plugs arnt very old either. I'm thinking maybe a coilpack is on...

as above this has got gradually worse. it started off juddering or possibly misfiring at 15+ psi now it has ended up 0+ psi and it does it! any ideas. cheers in advance.