Many coaches will have you take your slide step slightly towards your bowling arm, or body center, whichever side that is. Remember I said "slightly" because if you've ever clipped your ankle bone with your ball, you'll never forget it. IT HURTS!!
So your footwork could be part of the problem. The other thing is to free up the arm swing as much as you can. The more muscled your arm swing is, usually the more away from your ankle (body) it will be at release. Good luck.
--------------------
notclay
Lane Carter, Strike Zone Pro Shops - Salt Lake City, Utah