Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 04 Chevy Classic vacuum leak? › Reply To: 04 Chevy Classic vacuum leak? September 9, 2020 at 8:24 pm #963595 JeffParticipant It is normal for fractional engine speed variation when applying or releasing brakes, but if you are suspecting a vacuum leak it’s always good to check.