I am having the same problems, I went to the Nick Faldo Golf Institute in Orlando last month and basically my game has now gone to pieces.
They said that I was over rotating my shoulders bringing the club too far inside, my grip and set up was prety muck OK apart from my shaft was leaning forward down target line.
So, have been working on not over rotating my shoulders and keeping the shaft upright at address and now I can't break 90 (was shooting mid to low 80's before) I
was
playing to a steady 16.4 handicap.
I live on a golf course, so every evening (weather permitting) I go out and practice but I just don't seem to be able to nail it down
They video your lessons and send them to you as a WMV video file for future referance, If I can work out how to post the WMV video file I will put the on for you all to see, maybe some of you can take on board some of the info and maybe give some more tips for me.
Mike