I bought the car used with a check engine which was a miss fire in 2 of the cylinders. First thing i check was vacuum leaks and there was a crack in the hose shown in the video. I replaced it with a new one from auto zone. Later on, I started hearing a hissing sound from the same vacuum hose. As i rev the motor, the louder the hissing sound gets. Is this normal because I don't see any cracks in this hose plus its brand new. Sorry for the horrible video but you can clearly hear and see where the hissing sound is coming from.