I've noticed recently on my 92 GTA that there is an exhaust smell coming from the engine bay. It seems to be coming from the passenger side of the engine, but I can't seem to locate it. My question is where could it be leaking out, and would this cause a problem with performance? There's a cylinder next to the air filter, I have no idea what it is but I'm assuming it's something to do with emission control, it has hoses and electrical connections going to it. Could it be coming from there or how do I check?

Another bit of information, is that the catylitic converters have been removed on this car, replaced with straight pipes and when walking around the car while its running it does sound like a leak down there (there's a puff puff sound when you get around the passenger door hinge).

I know I might be worrying over nothing but rather I'd rather ask than not look into it. Thanks in advance!