I have a 2008 Prius that is having the slipping problem mentioned above. It does not slip out of gear like of the other posts, but if the car is put under a load, the engine races and the power is NOT delivered to the drive train (feels like a slipping clutch/transmission). Has anyone found the solution to this problem? The dealer (like the posts above) says that there are no errors being picked up by the computer, therefore, there isn't a problem with the car. GRRRRR Please help!