My 2001 Prius will hesitate anywhere from once to five times a day (does skip some days). It happens after backing out of the driveway and is put into drive (about 2 mph), going down the street (about 30 mph) or on the highway (about 65 mph), hot weather (about 95 degrees) and cool/cold (about 40-50 degrees), wet, dry, foggy, etc. The service people have driven it twice trying to get it to do this for them and they do have it on record. They said they are not aware of this in any Prius. Seems like it started at about 60,000 miles.