It's one year later, have you replaced the timing belt? Did you notice any difference before and after?
About the symptoms, here is my experience. The SC300 which I have just bought has 120k miles and it had the original timing belt. Before I had the TB replaced, the engine ran fine except that it often hesitated when I stepped on gas. The automatic transmission gear shift was less than smooth especially when it was downshifting during acceleration. It felt like it did not respond to the initial push, then it would lurch forward like I was hot-rodding. After the TB replacement and a 120k mile