Does it only happen at light throttle? My CAI used to whistle at light throttle. It could be an exhaust leak, although it doesn't really sound like a whistle. I don't think the throwout bearing would whistle either. I have a lightweight flywheel, and mine didn't cause a whistling sound...neither did my bad throwout bearing.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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