im suprised that most of the 'techs' here haven't told you to look into a new x or h pipe first. Rotten egg smell is almost always related to cat issues. Theres no real way to check them. But if the material inside gets broken/clogged it will definantly produce the smell and could cause driveability issues. I'm sure i'll piss a lot of people off with this post, but all im saying is that before you throw away money at expensive parts like coils and mafs, start simple. (theres always a lot of over-diagnosis around here and especially at dealers). A basic tune up with plugs,fuel filter as mentioned could certainly fix the WOT issue, and in my opinion there is a clear difference between the smell of a car running rich and a car with a bad cat/cats.