hi there,
i had similar symptoms, thought my gear box was faulty but to my surprise, it wasn't. After thorough diagnostics and testing, the problem was debugged! Faulty computer...I had an option of fixing it or replacing with a new one. I went with the cost-effective way and got it repaired. It had a couple of blown circuits and fuses which were replaced. As i speak, my yaris 2006 990cc 3 cylinder is peaking like a baby RS, crazy!!! It has over 30% more power, 0-100kph 6.2sec, was thinking that I had being driving for quite a while with some faulty components before all went dead..My current problem now is "cvt blowing out the breather", this happens once in a while. I have customized an oil catch can where I have inserted the breather thus no more cvt spill but more of cvt catch.. Apart from that, the car is performing exceptionally well... installing an AMR 300 and intercooler soon