Originally Posted by sacaledus
I did a search and found an old topic on this but it was really old so I thought I'd see if there is some updated info out there.
Whenever I mash the gas
I get a sulfuric smell
. Only during WOT no other time. Now the old post I read said it could be either a bad CC or worse a failing UIM. I just replaced the motor no more than a year ago and have been planning to get a highflow cat and magnaflow exaust. Should this smell facilitate the purchase of the exaust upgrades or do I have more of a problem here?
Actually, it'* likely a failing O2 sensor causing the engine to run too rich, thus burning in the cat. If you replace it, the only thing I would suggest is *NOT* to use Bosch, and use AC Delco.
If you run for too long with a bad sensor, you'll eventually plug your cat, so you'll want to get that changed when you can.
On the UIM causing that...I'm not familiar with that. A UIM failure will actually cause sweet smelling exhaust as coolant is burned.