power windows problem

I am having a problem with my passenger side power window in my 2000 F150. This problem only started after the =Ford dealer replace both accuators for my power locks. When going down it goes regular speed until it is about 1/4 of the way down. Then it comes to a slow creep and then after a few seconds it continues the rest of the way at regular speed. Has any one had the same problem or any suggestions
Thanks

there could be a ruff or "Drag" spot in your accuator rod..