Camry shifting problems

I own a 2007 Camry with a miserable transmission. Between 25 and 45 mph it will sometimes keep shifting and searching for a gear. Taking my foot off the accelerator at 45 mph causes the car to seem to downshift and it will not just coast. It does other strange things like hesitating when starting from a dead stop for a few seconds and then suddenly lurch forward. Traveling at highway speeds and braking when going over the crest of a hill causes the transmission to downshift to the point that the engine roars. Some of these things are intermittent and some happen all the time. I have taken it to the dealership 8 times and a toyota field service rep said everything is operating to specs. The dealership flashed to computer a couple of times and it help a little, but the problems still remain. Does anyone know if there really is a fix? Other people with similar models I talked to don’t have this problem.