High revving engine in first gear

[habs72465]

I recently purchased a 2003 4runner, V8. I love it, except that sometimes in acceleration from a stop, the rpm's run but the vehicle hardly moves. I either have to take my foot off the accelerator, or floor it for the transmission to engage properly. I took it to Toyota for service but they said nothing was wrong. I have about a month left on my warranty, so I'm getting a little nervous about having a problem down the road.
Has anyone had the same experience, or do you know something that I should?

Thanks,

jeff