Beefer, you've identified your problem. You're hitting with your hands and arms, not swinging.
This is causing your arms to come away from your body (get outside the target line), so the only way to 'save the shot' is to PULL them back in. Hence the PULL. Scientific, yes?
The problem is all the possible causes - but I'm sure you know this.
Another thing that could be causing your pull is ball position. If it's too far forward, your swing will be coming back inside (following an outside in path). Even a good swing with a ball too far forward will have the ball moving to the hook side.
If you need to go out again, try aiming more right. This serves two purposes.
1: If you do start to get the arms overacting, then your pull will put you in play.
2: Since you'll have compensated for the pull, you'll relax and put a great swing on the ball. This is usually what happens to me.
(Like last night. Expected the big slice with the new driver. Aimed way left. Hit it straight. D'oh!)