I have a V6-6MT coupe. Recently, on the highway, I got up to between 5000 and 6000 rpm (I've never red-lined it). When I did this, there was a strong smell from the catalytic converter. Is this normal? Is it anything to worry about? It's never happened before. I've had the car since June, and I have had the ECON button on most of the time and never smelled it. I've also noticed the car feels different when accelerating with ECON off. It may just be in my head, but I really think I notice a difference. Is the smell related to the lack of ECON button?