I think my catalytic converter is going bad. If it sits for while there is no smell in the car whatsoever. After it's been on for a minute or two it starts to smell like sulfur (which, unfortunately also smells like someone farted). The smell doesn't go away, and is present in city traffic. Its noticeable but not too bad. If I go 55 mph+, I tend not to notice it, if at all.

To me it means its a bad cat. Are there any tests to do at home to check this before buying a new one ($200+). Also, anything I can run through my gas line to take care of it? I thought once its bad, its bad forever, but thought I'd double check.

Thanks for your help, its getting hard taking the dog with me everywhere I go.

If a cat is working good it will get hot as hell. The easiest way to check it, is with one of those laser thermometers. just shoot it at the cat, then shoot it at the header. If the cat is 20 degrees or better hotter than the header it's working. Another way is to unbolt it and look down it to see if the grid is burnt out.

Sounds like it's stopped up. Muffler shops have a way to check pressure

It only has 46,000 miles on it, too.

you said cat has 46000, does the car only have 46000? If so factory warenty will replace it up to 100,000 miles free, But you can check the flow( or the lack of) by taking out the o2 censor and screwing a preasure gague into the hole, starting the engine and rev it up shouldnt be over 3#psi, the o2 sensor has 18mm thread, same as old Ford spark plug, use compresion gague end with hose to small preasure gague, Good Luck. JF