I am having this EXACT same problem on my 2003 2.7L. Have you gotten it fixed? If so, I am VERY interested in hearing what your dealer did. I called my dealer and they told me if they can't reproduce it, they can't fix it. Grrrrr.

Please let me know! Thanks!

BTW, I'm pretty sure this is a different issue than the one when you just put it in gear. I had that fixed, but I'm still having the highway speeds issue.

For the 2nd poster, I believe you are hitting the speed limiter. I've never done it in the Santa Fe, but I've done it in another car.