I have a 94 alty and it is hissing!!!...I know it sounds f**ked up...but it's the only way I know how to describe it. It's coming from the bottom of the car whenever I accelerate or the engine is under a load. It seems to be coming from everywhere, but more towards the middle of the car. It sounds like it is coming from each side equally, but can't really tell and it's really starting to piss me off, I know it's not the engine (???) b/c I just had it swapped....what the hell is this, it's most likely in the exhaust but what..thanks.