Is the tensioner pulley the same as the idler pulley on a 1998 Chevy cavalier?

No, the tensioner pulley and the idler pulley are not the same, although they serve similar functions in a vehicle's serpentine belt system. The tensioner pulley is designed to maintain the proper tension on the belt, while the idler pulley guides the belt and helps maintain its path. In a 1998 Chevy Cavalier, the tensioner pulley is adjustable to compensate for belt wear, whereas the idler pulley is typically fixed.