Hi I have a Yaris Verso 1.3 and have the same problem.It sounds as the engine is pinking but modern engines that have a computerised system just don't pink.I was at the local dealer and was told that perphaps the timing chain needs replacement.I was not covinced.I sprayed some penitrating oil on the belt that drives the aircondition compressor and the power steering pump and that noised disappered for a couple of days.When it have returened I put some engine oil on the belt and it lasted for about two months.But now I am going to change the belt hope that it dosn't make that irritating noise. ← What do you mean about pinking?? :P Well i already thought about that noise to be from the alternator belt, that it could be slipping, but i had that problem on my Golf GTD, and the noise was quite different, it only gone when i replaced the belt. :P (but Golf's case was really more serious, cos in the winter nights, it kept squeeking wakin up the whole neighbourhood and when I used high range lights daamn it seemed i was hurting him ) ← Hi Mad Ness. Pinking meanes when an engine timing is not correct ex.when the engine is retarted or advanced.But the Yaris engine does not have a distibutor so it is impossible to go out of tune.