When you start recording the ai line drive really really slowly across the s/f line in your first lap Like 20kmh. First lap after that is a throwaway lap. Then do at least one more lap until you get something you like. When you exit the game you should now have the candidate in your ai folder. Also if you have multiple configs the candidate files are made in the config\ai\ folders. I had this same issue and going slowly over the s/f line fixed it.