 At a steady speed, steady rpm between 2000 and 3000, on flat surface the rpm suddenly drops 200 to 500 rpm then jumps back up to cruise.Does this every fifteen seconds or so almost all the time.Dealer service says "Oh yeah, that's what Corollas do""There's no fix"It's VERY annoying.May have something to do with Downhill Braking assist of the electronic transmission.VERY annoying.Many other owners have reported exact same thing and Toyota doesn't appear to be doing anything about it.I would avoid Corrollas until they fix this.