I have a 04 G35X, there is a leak in my exhaust right under driverside seat, i have no idea is it coming from cat? I don't know what to do, any advice folks?, thank you.

 

Bryan, the best way to discover if and where you have an exhaust leak is to stop by your local "Muffler Shop!" They can not only locate the leak but fix it too...easy huh?
Gary

 

OP please read all sub-forum header descriptions, this one specifically says "No Car Questions". That being said I'm moving you to the appropriate sub-forum, you're welcome.

 

It's probably a flange, flex pipe, or something like that. You can put some SeaFoam in your crankcase and look to see where the smoke leaks from. I'd recommend doing this outside though, I did this to find out my flex pipes were bad. I put a new Y-pipe on and then had Meineke remove the flange from my mid-pipe to muffler and weld a sleeve in place, since that was leaking as well. I don't plan on doing anything with my exhaust so this was an acceptable solution.

I think it cost me about 400 bucks total, buying the y-pipe, installing it myself, and then having Meineke weld the sleeve on.