I everyone! I'm new to the g37 world, graduated from the Honda world. So I just bought a 2009 s model with the automatic tranny. I am noticing a rattle noise coming from the lower front of the motor. When I rev it it gets quieter at about 2500 rpm. Doesn't seem to be internal. Almost like a loose exhaust, bit I really don't think that's it, due to the location. Any help appreciated.
Ps: bought the car used with 62,000 miles and no warranty.

 

Welcome to the site and congrats on your G. Might be a cat heat shield, those are notorious for rattling, but if it's lower front could be anything
If you can get it on jack stands and give it a good inspection you might find something loose. GL

 

Thanks! I'll check that. I plan to get it in the air tomorrow.

 

Now that you've mentioned it, I think it is the cat heat shield. We will see after I put the exhaust on this weekend. Thanks for the help blnewt!

 

Good luck, hope that solves your mystery

 

Also check to make sure your cat isn't busted. I would get a "marbles in a can" sound after revving the engine. The content of the cat had broken loose. I had one cat replaced under warranty.