Hello guys,

I have a manual IS 220d with 180k kilometers on the clock and I started to notice a strange noise.
Basically, if I'm accelerating in gear, I hear a strange knock from the engine, specially at higher gears it seems.
If I accelerate in neutral the noise isn't there.

I took the car to Lexus a couple of weeks ago to do a checkup for another issue (car spits antifreezer sometimes) and all they found was a small leak on the water pump.

Could it be injectors? Car has the typical knock at idle at cold temps for a diesel engine but this knocking under acceleration while in gear is driving me insane.
I've looked around for videos here and on youtube and didn't find anything specific but heard some people talking about tappet noise.

Oil level is fine and I'm using the recommended 5W30.

I'll make a video if possible and post it here later.

Edit:

Looked around and it definitely sounds like injector rattle. Previous owner did say he took the car to Lexus for the 150k kilometer service and the chief tech told him one of the injectors wasn't 100% but it was nothing major and wasn't worth to mess with it yet.