Only two weeks before it is scheduled to debut, Knight Rider has lost the voice of KITT, the talking car. NBC disclosed that General Motors had asked Will Arnett to drop the voice-over role, maintaining that it conflicted with his work as the announcer for GMC Trucks. (KITT is a Ford Mustang.) Arnett had previously recorded his Knight Rider work, which had become part of the already-completed Knight Rider episodes. NBC said Wednesday that it will replace the Arnett tracks in the next week with new tracks recorded by onetime Batman Val Kilmer. (Presumably the makers of the Batmobile will have no objection.)