Hello guys, I have tried to search around but couldn't find anyone has a similar problem. Please see this: https://www.youtube.com/watch?v=Jt5tRUecgjw Basically it's making a hiss noise intermittently (no pattern) when the car is cold. The noise goes away completely after the car is warmed up. Initially I thought it was the heat shield on the exhaust manifold but the problem persists even after I replaced it with a set of extractors. Any suggestion would be greatly appreciated! Thanks.