3L d4d 2012 clicking noise no power

[Abecronje]

Good afternoon. I recently bought a nice 2012 3L d4d dc 4x4. .220 000 km full service hustory with dealer's I have one question .
I hear a slight tick tick in engine area.and when driving it sounds if it goes louder/ sounds rough.it then takes a while to pick up speed. Then does not feel like a 3L.And other times it is quite and picks up speed quickly and smoothly. I hand it by toyota and did ask them to take it for a driveon the highway to make sure everything is okay.i also asked them to check via their computer if the injector values are still in spec.they said bough times all is okay and good.
Please give me some advise or a direction of where to start looking.

Thanks
Abraham

[Jaws]

Could be the VNT actuator. Although generally they don't give issues

[Abecronje]

The what?
The where ?
First time i hear of something like that.
If i may ask what does it look like or where is it situated? Thanks for the reply

[Rigger]

The VNT or VGT stands for veriable nozzle turbine or veriable geometry turbine. Inside the turbo is vanes which changes its position so that you have optimal boost at all rev ranges.