Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › my 2000 jeep 4.0 cherokee is revving really high › Reply To: my 2000 jeep 4.0 cherokee is revving really high July 22, 2020 at 7:40 pm #961926 JamesParticipant High revving at start up and stays there usually caused by vacuum leak. Cover the throttle body air intake and see if it still revs. If it does you have a large vacuum leak.