my exhaust smells like rotten eggs. is the cat most likely the cause? or could it be something else?

 

You nailed it.

 

rotten egg smell is caused by burning sulpher. Some gasoline blends have a higher sulpher content then others. When the sulpher burns in the converters you get that smell. It is normal but try changing gas stations if it really bothers you.

 

If the smell is very strong it is most likely a cat going bad.

 

If your running to rich it can smell like rotten eggs, when someone floors it to pass you, is that the smell, thats when your computer is sending excess fuel or is in open loop, if I remember right. I don't know if that helps.

 

my trucks exhaust smells like this also.... mayb their is a fuel additive are something to clean them?