what are the sign of a cat goin bad?
do i get a bump at idle?

 

basically goto your pipe and smell it...if you smell rotten eggs then its gone. best diagonsis you can do imo. or take your cat off and look at it. these are the only 2 ways to know. more posts on this topic would be pointless.

 

i guess mine is gone :/

 

since you have a 99.... the bump at idle is more than likely ignition coil related...

 

What do you Mean the Cat Is going bad. You talking about the Catalytic Converter? I doubt that would go bad on a car that was Made In year 1999. It would take years for the Cat to go bad, not like 5 years. it would not go bad in 5 years.....


http://www.auto-repair-info.com/cata...converter.html

 

anything can go bad...anytime..

 

i smell the rotten egg smell that why alot
or should i throw some of those cat cleaner in my gas tank?

 

I agree with you on that, but how many times you have heard on the Maxima.org, or other message boards, people saying their Cat is going bad. That is Kind of rare...... but then you are right it could go bad at anytime.

 

I say call Nissan of America, I think the Cat's are coverd above the Manufacture warranty. First go to local Mechanic shop and have them confirm that, it is for sure the Cat.