2003 Pruis engine Knock

Try cleaning the throttle body and MASS sensor.

Thank you for the reply, I've tired that it didn't change anything, at a local garage they said due to the high miles 163000 they see alot of these engines with the same problem.

In your car, the engine runs on the battery power for the first 8-10 seconds, until it starts. Check if your main (high voltage) battery is at low charge when this happens. Does the same thing happened if you drive around for a while and then turn the car off and on?

It does make the same noise once the engine is restarted when warm but only for a few seconds.