Zafira Gsi Running Problem

Hi Iv just got another problem now when i put my foot down car judders and misses really bad about 3k and will not rev much more i unplug the air flow meter and it runs almost fine apart from a little miss about 3k so i brought a new airflow meter pluged it in and its still doing it has anyone got any ideas what it can be iv changed plugs coil pack and the car has been checked for boost likes but all seems ok apart from it smoking to as in my last post