Hissing in the rear of the car - HELP ME

[drock608]

I have two self made conclusion and that my problem is either a fuel pump or an exhaust leak near the catback. My money is on the fuel pump because it seems that im getting less mileage for my gas. But just like the title says, there is a hissing sound that comes on after the car is driven for about 30 minutes straight. Kind of sounds like the fuel pump just ALOT louder. I think there also might be a mild loss in power.

[shotofvodka]

i got that same problem. mine is a hissing/whinning noise. strange thing is when the gas tank is full theres no noise,but when its low on fuel say quarter left it makes that sound.i heard its a pain to put in a new one.

[drock608]

What is the problem though? the hissing sound only comes on after the car is driven hard or driven for an extended period of time. There is no difference whether the tank is full or empty, all depends on the how it was driven prior. PLEASE HELP!!!!!!!!!!!

[02z28ls1]

There is only one real way to pinpoint a noise to a pro mechanic and that is to get it to make the noise and then find the source.This will mean getting under it an listening-maybe you can find a garage that will help you-alot of shops diagnose stuff for free-just dont expect the guys to be ecstatic about not getting any business in return.But a professional like myself will help you if you don't take up alot of his (or her) time.