I have a problem
 

Maybe someone can help me out i am having a problem with 2007 Hyundai Elantra 2.0L GLS, the problem is that there is a hissing sound only during hard accaleration from 1st to 2en gears, it sound like a turbo blow off valve? People keep telling me that it could be a vacuum leak and other people say other things. Has anyone else had this problem?

It could be a vacuum leak at the intake manifold. Hard to tell over the Internat. I'd suggest a dealer. It should still be covered under the warranty.

Warranty ran out about 2 months ago. :-(