4.7 exhaust leak

So i bought my 1st gen came with headers, unknown brand, but i have and exhaust leak at 1st when i bought it it was fine but now im annoyed of the sound, sounds like im driving a broken down truck, so where can i start to fix it? Gaskets studs tighten?

Im getting a fuel odor from my evap system

 

as far as I know your gonna have to pull the headers and reinstall a new Toyota OEM gasket. I would make sure you have decent headers also as its a shitty job and don't want to have to do it again.

 

It is a shitty job and if you have a 4x4 ohhhh boy you gots reals problems. PITA

Aftermarket header flange from many of the mid priced brands down usually are not straight. I've seen a few of the big $$ units even have a little bit of a wave to that flange.