I'm not sure about the 2.4 ... If this was my 1.9 I'd be checking for leaks before and after the turbo as revving seems hesitant ... Get a squirt bottle with water and washing liquid, while the cars running squirt round any possible air pipes and joins, look for bubbles or change in engine sound. Helps if someone else's does slight revving too.... Failing this, run some redex through it and look for improvement then .... Check the boost actuator, swirl flap operation, N75 valve, jammed VNT vanes.
One of these will be your problem, though I'm sure N75 valve and swirl flapswould bring up a engine check light .... Boost actuator and jammed vanes maybe not.
Have you done any work recently ??? If so what ???