94 gt, gas fumes or converter?

Okay just recently my car has had this odd smell on the outside of the rear end. It's kind of like a gas smell but maybe not. There are no gas leaks anywhere. I haven't seen any puddles or anything. Someone said there may be a leak in the top of the tank just big enough that the fumes escape. I think it's my converter that makes this weird like rattling sound when the car is going and it is around 3000 rpm's. When I've been underneath I haven't seen the heat shield hanging or anything. On my way home today I had the window down and the car really really reeked especially when I would get to a stop it smelled kind of like gas but not really. But there smell is still there after the car has been sitting for hours. The converter makes sense though because it would seem like there would still be emissions inside the exhaust system because the car would be off and they wouldn't be pushed out. Anyone have any idea would this could be?

Deffinately sounds like a bad catylitic converter. The raw gas smell is probably caused by a bad 02 sensor reading (caused by the bad cat) causing you to run rich / push raw gas out of the tail pipe, ontop of the normal "sulfur" bad cat smell. I would deffinately say gas.

So I should get the converter fixed and that should make it fine right? would I have to replace the o2 sensor or is it just getting a bad reading?