When I start the car the vacuum of the power locks keeps going and going 'till it finally stops after few minutes. The locking and unlocking works fine.
Could it be a vacuum leak? And if so how do I pinpoint the faulty hose?

 

it probably is a vacuum leak check for leaks on pipes connected to pump (in boot behind o/s/r carpet) with a vacuum tester
but firstly check operation of fuel filler cap locking element this is the usual suspect
regards
conect