Man this is so weird. I finally was able to go to the driving range today(despite a strong wind) and I had the same exact problem. No matter how I tried to work it I kept hitting it fat. So I did what some of you have done and started hitting half swings and boy what a difference. I finally came to the conclusion that I'm doing something wrong at the top of my swing. I also inquired on lessons from the local pro so he could help me with this problem.