UIScrollView animation fails to complete on iPhone 3G

Question

I have a UIScrollView that scrolls horizontaly between subViews from user flick gestures or touches on the UIPageControl. Flicks work perfectly on a 3Gs, but often the animation stops short on a 3G, so that the next subView is not centered. A second flick will complete the scroll to the correct position.

The animation is flawless on both devices when the user touches the UIPageControl, which calls a method that calls [scrollView scrollRectToVisible:frame animated:YES].

Any ideas?

Also, how would you disable flick gestures, and instead scroll between subViews when the user touches the right or left side of the screen (as in the eBook reader Stanza)?

Thanks

jk