when the car is parked, there is no hissing noise (that is when you press down on the accelerator) But when the car is in motion it makes an aweful loud hissing noise and stays. Its terrible on the highway...What might be the problem?? Headers?? Exhaust?? When the headers were first installed, thats when some minor hissing sound came but the shop couldn't recognize it... Never had turbo or supercharger on either..


02, Honda Accord Cpe 4cyl. EX

 

right after i installed my header i started to notice a little hissing sound once you get pass 2750 rpm, but thats only under accleration

 

you may have a blockage in your exhaust system