2002 automatic jeep wrangler - high-pitch whining while in idle, as well as while accelerating. Seems to come and go once I brake. Has new brakes, new belt and recently replaced battery. Now, while I have foot on brake, it will try to lerch/accelerate forward on its own and rpms will rise on its own. Also, while in park, rpms will rise from 1000-2500 or so - just for a second or two - then drop back down to 1000 or so. From researching other threads, maybe a vacuum leak?