Last night I had the car (99 SE Sport MTX) up to about 85 for a while. I don't normally drive faster than 70, although this certainly isn't the first time I've had it beyond the speed limit. Point is, the floor of the car got pretty hot after a couple minutes of sustained speed. Never experienced this before, and I'm worried- the car has 72000 miles on it and if the cat is going to go out, it had better hurry. Or is it something else?