Can a QB scramble outside of the Tackle, then back behind the center and still be called for intentional grounding when he throws the ball away? I thought once he goes out of the pocket the "Pocket" was gone for good. What do you think?

Your thinking is correct: NFL rule 8-3-1, Note 5:
When the ball, either in possession or loose, leaves the area bordered by the tackles, this area no longer exists. All intentional grounding rules apply as if the passer is outside this area (as stated in Note 1 above).

Thanks for the quick response. I just found this site today. It is very informative. I am sure I will have more "officiating" questions.

Bring 'em on, were happy to help!

Just remember to do what you did with this question; specify if it is NF (High School), NCAA (college) or NFL you're after. The rules differ greatly.