I remember a drill where to feel the follow through right after impact, you actually learn to throw your clubs in front of you. Yep, literally throw the clubs. I haven't had the luxury of actually trying that heh, but think it does help give a better feel of the swing right after impact.

Would you happen to be breaking the left wrist too soon thus bringing the club in around right after impact? How you hold your club at follow through (high or low sideways) would also be a very good indicator.