Nissan Repair: NISSAN CEFIRO WONT PASS 3000RPM, nissan cefiro, turbo diesel

Question
hi. my Nissan cefiro won't pass 3000rpm. i have changed the starter., given it a full service (including changing the fuel pump and fuel filter) and changed the two sensors. only difference it made after changing the sensors was the idling was much better but it still gave a hard start and won't pass 3000rpm and i can hear air is escaping somewhere but can't find where. please advice.

Answer
Hello is this car a turbo diesel or simply a turbo if this is the case the air escaping is coming from the turbo pipes that should be located at the front of the car below the bonnet and the air is not passing through he system as it should if you could please tell me if it is turbo diesel or petrol i can try and find out more information for you as the precise location to look for the problem area