Sure Cr0 has his own opinion but to me it sounds like:
1, are you are setting up too early and 2, not snapping off the lip so that your knees/board can follow your upper body smoothly.
When you set up, your upper body should still be winding in the direction you are going to spin as you pop off the lip. The pause you describe is what makes it hard to get your lower body to fluidly follow your shoulders/head/arms. The more tension you can create (by increasing the angle between lower and upper body as you pop), the faster you can spin but you should never pause the wind up motion. That is why the timing is so important. It has to occur early enough to get a lot of tension built but not so soon you pause your motion.
Secondly, if you don't pop off the lip and help put your board in motion, it will be hard to snap your board and knees around to follow your upper body. Some people suggest carving off the lip so you can come off your toes or heels. I prefer to always pop off my toes.