I have a Sienna that we purchased in Feb 04 with exactly the same problem. If we are on a SLIGHT incline, it will open then close on us again. Previously we also had a problem with the door handle sticking, which would make the door open & close back and forth forever. We got that problem fixed, but the dealer tried to tell me that it's normal for the power door to close unexpectedly, which is BS. Toyota Customer Service (1-800-331-4331) told me that only if the dealer finds "something of concern" - which he couldn't describe, would they cover it under warranty. I plan to go to another dealer, but this doesn't make any sense at all. Why would it be so difficult to fix? Did you get your door fixed? What did they do?