renault trafic no throttle when started?

i have recently purchased a 2004 renault trafic dci 100 bhp, when i start the vechicle there is an delay in the accelatration pedal, in the morning its barely noticeable but as the day progresses and regular stoping and starting the delay has been as long as 5 mins ( im a taxi driver).

ive replaced the EGR, air flow meter as they displayed on the mechanics computer

whats my next option injector / turbo / cramkshaft sensor / service (done 5k ago) im lost

thanks

tommy antrim
August 2010