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.
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.
Just had the computer fix applied to my car and the transmission no longer acts as though it had a mind of its own.
No more spastic jumps of the rpms and no more slowing down on its own.
It now acts like a normal car.
Too bad Toyota never owned up to the issue.
I had to take the info from the guy who posted above and then show it to the service techs.
Hey Guys, just go to www.toyotanation.com, click on Toyota Corolla section and read about our car.
There is lots of useful info, and it is free:)
I did not have this problem on my car, but I did the update anyway.
Enjoy your cars!