Great, thanks very much for responding, Filehorse. Now, just yesterday, out of the blue, it started shifting properly. This happened to me with my first Rx300. I took it to transmission shops but they never could get it to fail, so they found nothing wrong. Then of course, as soon as I get back into it, it fails again. That really complicates things. But the code then was the knock sensor, and one shop just knew that could cause it, from experience. He fixed it. Cost about $1100 because the intake or exhaust manifold, I forget which, has to be removed to replace the sensors. I bet it's probably the same thing, but of course, I don't know for sure. Thanks again.