Car help! Smells like Rotten Eggs

[sburns]

OP - did you get around to resolving the issue?

So far I have changed the engine filter, it was fine, the cabin filter it was in rough shape, changed it. Just to make sure can't hurt.
Also the last 2 times I have gotten gas was from Petro Can, it seems to have made a difference, the smell is mostly gone now. Not reeking like before. Most of my driving has been on the highway so the car has gotten up to a good driving temp. Maybe not quite a Italian Tune up.
Again no check engine lights so hopefully this all comes down to bad gas. It's hard to believe that, as I would think, all fuels should be created to the same specs for such a regulated industry and to the expense of our vehicles.

 

[Trials]

Is not really the result of bad "spec" fuel, is the result of pollutants in the fuel. Using leaded fuel for example would deposit material on the cat which will not burn off and that destroys the cat. Rotten egg smell is usually associated with sulphur which is why some suggested the lead acid battery which can be a source of hydrogen sulphide. Sulphur is not a normal component of gasoline, sulphur IS commonly found in low grade fuels such as low grade diesel, so if for example if the fuel carrier was using the same storage or delivery tanks for stove oil as their gasoline, that would potentially introduce sulphur into the gasoline and your cat might stink as a result of sulphur in the cat. Hydrogen sulphide can also be from biological sources, bad water or 'sewer gas' smell is an example. Picture your cold cat converter with bad smelly water in there from condensation, you engine fires up and boils that stale water, then the potential pollutants in that water reach flame temp and you smell that until it is all burned off.

Fuel quality control ends at the refinery, the stuff we pay for at the gas station may contain anything.

 

[sburns]

Wow @Trials that was an impressive answer, not typical of your usual responses, much appreciated!

 

[bitzz]

Fuel quality control ends at the refinery, the stuff we pay for at the gas station may contain anything.

... and you should know that because of Toronto's topography, the bowl that is the "golden horseshoe" Toronto is the dumping ground for bad/contaminated fuel for all of North America.
If a refinery screws up and their gas has, let's say too much sulfur; off to Toronto it goes.
There was a tank in California (a couple of hundred thousand litres) that somehow got radio active in the '90s, off to Toronto it went.