voyager 2002 CRD LX screeching at 2000rpm
 

This is a Grand Voyager 2002 CRD LX (2.5l) at 125000 miles. There is a deafening screeching coming from the engine compartment at high engine load between 1750-2500 rpm.
As soon as rpm is over 2500 the screech stops in less than a second. It only happens at (almost) maximum throttle.

Apparently it is connected to high engine load only which makes air inlets and fuel pump suspicious. Problem is that it cannot be reproduced when the car is not driving, which makes trouble shooting difficult. There are no other problems with this car apart from some oil leaking.

I was wondering if anyone has had this problem before and give me some markers where to start with this problem.