revs drop in yaris 2000 1.3 vvti sr

[nalin]

hi there,
i have just recently bought this one and i have noticed something is wrong.

whenever i press accelerator - first reaction of the car is revs drop - it does not matter if its while driving or on neutral. stronger i would try to accelerate - bigger the drop is. i am not very god in cars - should i start to worry?? is there any simple solution for that, other than seeing mechanic??

i am looking for a manual for this car as well, any ideas where to find it??

regarding timing chain - does it have to be replaced, same as cambelt at any point??

thanks