sulphur/rotten eggs smell from exhaust

[harriman]

Hey all,
So today I was driving my car and I briefly smelled rotten egg exhaust. I recently just changed the oil, oil filter, air filter, spark plugs, fuel filter, and belts. Last year I replaced the CAT, both 02 sensors, mass air flow sensor, drive shaft bearing, idle control valve, and guido (spelling).

I'm thinking that this smell is due to a batch of bad gas I picked up at some no name gas station. Also when I'm under heavy load going up hill in second or third gear I can hear this kinda of whining sound.. something new.. since this new batch of gas. I opened up the hood and located the sound to a black roundish thing attached to the intake manifold (big metal thing that has BMW stamped into the top).

I'm crossing my fingers that it was just a bad tank of gas. Any ideas

Thanks again

-Harrison