Daihatsu Cuore L701 idle speed problem (or not?)

Hello Daihatsu lovers,

I'm also a daihatsu lover, i own a 2001 l701 Cuore wich has made me very happy. However, recently, i started to experiment some issues with my lil' car. After an engine compartment wash, the engine would tick over from the 1000 rpms to as high as 2500 rpm's. This starts when the engine warms up. Weird thing is that the check engine light hasn't turned on. I was told that it was probably a faulty sensor from the throttle body. I already replaced the idle speed control valve (wich i had a difficult time finding it since in my country this is a rare car) but the problem persists. I also did a throttle body cleaning, and the same behaviour. I don't know what to do now. There are two more sensors that i would like to try (throttle position sensor and the vacumm sensor) to replace, but maybe some daihatsu expert has some tips for me before i decide to do this. How can i know if this sensors are working?

Thanks for any help you guys can provide.

Regards.