Originally Posted by VikH

It's your AC. I am assuming you are running your AC while you are performing these runs. When you WOT, your A/C turns off. This causes the egg smell. Do a test. Turn on the car and the air conditioning. Then turn off the A/C condenser. See if you get the smell.

Originally Posted by Jesknorr

I've been searching for the solution to this and have found it. In the trunk there are pressure vents or air outlet vents, vent valve, rear quarter outlet vents, are the names they have been called. They are accessed from the trunk one on each side, under where the amp is and on the other side. They are black vents with a rubber flap these break or even come off which in turn allows the exhaust to enter the cab of the car. All you have to do is replace them. $20-$30 for each one!! Also will fix the issue with the stereo not working when it rains due to the condensation that builds up around the amp!! No need to replace your cats or anything else!! I'm telling you, check these first!!

Originally Posted by mistervj1

What's the name of vents? So I can purchase on eBay?