Hey everyone! Really need some advice on my my car is making a weird noise. Okay so i took it to infiniti dealer to have it checked out. Looks like it was the catalytic converter that they said needs to be replaced. It took them roughly thirty minutes to figure out what the issue was ( which i think was way too fast to figure out a problem like but idk i could be wrong) anyways the noise is like a rattling noise when the car is stoped the noice gets very noticeable. Its like a tapping noise kinda thing like if metal to metal are touching. Some friends say its something with my exhaust. ( by the way my whole exhaust system is stock) ( infiniti g37s 08 ). Other friends say it could be problems with the transmission. I really need some advice on how i should take it to a mechanice to have my whole car inspected with out a big charge. Also any advice / ideas will be helpful on what i should do if it is the catalytic converter like what are some good cats for cheap or whatevr. Please reply to thsi posting as anything will help thanks guys!

 

weird coincidence... decided to take the g to the gym this morning to stretch her legs out..
been under cover for the past several weeks.. noticed the same thing.. recorded a video of it with the intention of posting it..
it sounds to me like its either a lose heat shield or the cat... doubt its transmission as i only notice it during idle and continues briefly after shutdown..
im just goin to tack it up as cat... gives me an excuse to go hfc..

 

had it happen to my other car .... loose exhaust heat shield - made a horrible noise

get a long-handled screwdriver and crawl under the car, then start poking around at the heat shields. after i found the culprit, i secured it with some big band clamps from Home Depot.



problem solved. i wasn't worried about looks because you can't see it, but if you're a stickler, you could get the heat shield replaced. i would certainly check this out, because factory cats are $$$$.

 

It sounds like you're having this issue:

http://www.infinitig37.com/TSB/1SB19.pdf

 

I am also having the same problem..I drive a 09 G37 S Sedan 6MT and the clanking noise is really annoying me. I notice it when I am idle, but it goes away time to time...my back exhaust tip is a little bent, may that cause the problem too?