Yaris P1 1.4 D-4D 2002, a strange tapping sound while accelerating

[Akikiv]

Hello!

Does anyone have an idea what could cause a strange tapping sound while accelerating? The sound disappears after acceleration and it's not present all the time while accelerating, mostly it makes the sound while the rpm's about 1300-2000. There's no such sound while on idle or at a steady speed.

Any help would be appreciated. Thanks!

[Fluxtasy]

I think it's engine knocking. I do hear this sound too in a situation where you are are driving up a low incline road with RPM in the 2k range. Maybe someone else here can explain better.