how do you know if your cat is starting to go bad??? and why would a cat go bad. The reason why i am asking is because when I drive my car in the morning i sometimes get this weird rattling noise and vibration that i can feel through the car floor and peddle. Also my car does not start well after i have been driving a while and letting it sit. it starts up well but dies and have to restart the car. So Im wondering if its the cat?

 

Do you have any SES codes? there are many items that can cause ac at to go bad.

Too much fuel / not enough fuel, etc. And those problems can point to OTHER problems, ultimately leading to a bad car. (bad MAF (lean), bad O2 sensors (rich), etc.

 

no codes but i get this rattle and was told its prob the cat.

 

A rattle can be ac at, or a heat shield. Inspect, report back.

 

Do you get it when you start the car? rattle noise lasts about 2 sec at the most? I have the same problem and it seems to be my cat. the dealer said

 

my cat is on its way out, i'll sometimes go to start the car, it acts like its gonna die, and then kicks in....and as far as why the cat would fail.....try breathing straight carbon monoxide for 5+ years and see how you do...the things are like anything else in the world, eventually they break down.

 

NmexMAX what is the ac at. not sure what you mean. Also The rattle only happens when i gas it in the morning. After driving awhile i cant get the rattle to happen. and yea my car acts like its gonna die, and then kicks in all the time. I guess it is the cat.

 

ac at = a cat

 

Could be the cat. I know the 2001 Maxima's had horrible problems with cats going bad so it could easily be that. Just get one of those cheap magnaflow cats off ebay for $44.

 

proof?
stats?

 

hmm i seem to have the same problem as you. my cars been throwing up the cat code for almost a year now but my mechanic said i shouldnt worry about it unil i start having performance issues. well now im getting that odd rattle like you are.

 

thanks.

00-01's had problems with their MAF's, which ultimately led to a bad cat.

 

my check engine light came on two months ago the threw out the cat codes and when i changed the battery in my car a few days after the light went off and never came back.... now i am just waiting for the my car fall apart on me