Hi everyone, I’m having a problem with my 2012 G37x with 83000 miles. Currently whenever I’m driving my car, once I turn on the AC or heater I get a weird smell that comes into the vehicle. It’s like a mixture of gas and exhaust fumes that come into the car, I’ve checked the fuel dampener no leaks, I replaced the exhaust manifold gasket due to a leak when I brought it to the mechanic, my exhaust line was sprayed down with soapy water and couldn’t see any bubbles. I’m currently very confused on what the issue can be. Any help is appreciated!

My car has kinetix HFC (it’s been a year now that I’ve had them, the smell started recently so it’s coming from there) and a muffler delete