Originally Posted by patrickch
+1 to the low grade gas, or may be you have some rotten eggs under your seat.
try a bottle on good quality fuel system cleaner, such as Techron, it may help, worth a try for $7.00
I would not recommend this. All these fuel additives do nothing to the cat. If anything they cause the issues. By cleaning your fuel line and injectors you are actually burning the crap out which in turn sticks to the platinum in the cat. As mentioned before your fuel to air ratio is off and you have unburned gas (possibly). That would also be the cause.
Find a big ass hill gun it up the hill, if it's the cat then it will stink 10 times stronger. I had that on my volvo, took it for a trip in the mountains, smelled bad for a bit but then it cleaned it self out. I guess from all the driving up the hills and mountains it got super hot and burned it self off.