im having an issue with my ep3
everytime i gun my car theres a loud hissing sound coming from the front im not sure whether its the exhaust manifold gasket or the header itself
and im losing power im revving up but my car wont go im stock to 60 mph in third gear in high revving,
car has 127k miles new clutch, modded airbox and midpipe thats it
so my question is does the OEM header has a hole thats leaking
or does the gasket will go out if you take off the header??

 

sounds like ur clutch is shot. if the rpms go up but the car goes no where that means ur clutch is slipping. An exhaust leak will not cause the car to loose power and/or not go over 60. replace your clutch asap and while ur at it change the rear main seal.

 

what about the hissing sound on the bottom?

 

and oh yeah i just changed the clutch