I've installed a new CVF racing saginaw pump with proper pulley, and a mid 80s fox "used" p/s rack in my 1982 mustang, and I've noticed that the power steering isn't working correctly on start up. It only starts to work when i get moving down the road a little bit. However when I come to a stop again the p/s seems to be working normally, and just fine for the entire drive after it starts working. What could be the problem, could it still be air trapped in the system causing that?