Couple for FS2002 questions

I've had FS2002 for about a year and a half but finally decided to ask these questions. I have a problem with AI aircraft getting stuck prior to takeoff. It usually happens at the position just prior to the hold-short. It will just sit there while other traffic backs-up behind it. I've noticed it more and more since I've have installed more FP's. It randomally happens at different airports and to different aircraft. I've check the AFCAD and there isn't any problems. Is this a MS FS2002 bug? Also my FS2002 hesitates momentarily. It's only for a split second but it's noticiable. Any thoughts?