i was wondering what is 'normal' for the duratec to idle at (mtx if that makes a difference). i was sitting in my car tonight waiting for a parking spot (damn university parking!) and noticed i'm idling at 750, but like clockwork, every 22 seconds it revs up to 1000, then back down. is this normal?

98 SE 24V DOHC MTX -17" konig tantrums wrapped in 215/45ZR17 Falken Azenis ST115, sho shop cold air intake, arospeed sport muffler, taurus 24V badges, custom painted grille, stock foglights added,