PGA, why driver not solid; check your power sources for leaks:
1. Body turn
2. Wrist Hinge
3. Weight Transfer
4. Release
Your answer lies within one or more of these power sources, nothing else.
Start examining, are you turning left shoulder over right instep?
Are you gripping the club in such a way so as to prevent hinge?
Are you not giving backswing enough time to complete?
Are you not following through past impact to finish?
Are you not transferring weight to inside of right foot?
Are you transferring weight beyond inside of right foot?
Are you so tense that the clubhead is not releasing? Gripping to tight?
Let me know what you find out.