I haven't gotten that fast in my Crossfire, but if it could be the cat converters. When they run too rich for a while you'll get the sulfur smell. And I'm sure you had your foot to the floor boards to get up to speed. If it goes away after a short spell of routine driving you're okay. If it continues, something is giving your computer a signal to run full rich. Any vehicle I've had over a 100 didn't have cats on them. I love my Crossfire, but for raw guts I miss my '70 SS 396.