Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 04 Chevy Classic vacuum leak? › Reply To: 04 Chevy Classic vacuum leak? September 12, 2020 at 6:32 am #963634 Mark WahlbergParticipant I was assuming a leak by the change in engine speed alone but I haven’t checked fuel trims yet so that would be my next step then. Thanks guys. I’ll grab one of those BT readers for sure.