Hi just brought a tdci focus 03 90,000 mile serviced from new having problems in the morning I start it up and it smokes loads and sounds like it misfiring running rough I have to rev it up till it stops and the smoke stops when I drive it it hesitates juddering then it goes fine had it checked on snap on dia machine it came up with maf sensor so I got a new one and cleared the codes then took it out for a spin and still happening the same code came up again would the map sensor cause it and the turbo seems to spool up when idling any ideas thanks

it could be a stuck or gummed up egr valve, these can be removed and cleaned.