Hey guys,

Lately it seems that if I stab the gas for hard acceleration I can hear a rattle coming from (what I believe to be) underneath the car. This is happening more often than not and it's starting to drive me insane. I'm going to take it into the dealer soon but I want to point them in the right direction. I've read other threads mentioning heat shield but quite honestly it sounds like it's coming from the cat. I took it to the dealer recently because my exhaust crackles (like when you turn your car off after a long drive) loudly while idling, dealer advised it was normal and sent me on my way. Thoughts?

As well, my car seems to float all over the road. It's hard for me to keep it in a straight line, however my steering wheel position seems fine, and it doesn't pull to either side as if my alignment was out. Thoughts on this as well?

Most dealership mechanics wouldn't have a clue how to fix an exhaust rattle, their knowledge tops out at "It's on there!" Take your G to a knowledgeable muffler shop and tell them what your issue is. A G35 floating, I've never had that sensation! If you car isn't tracking correctly there's a good chance your alignment needs correcting. Again, I wouldn't go to the dealership....find an independent alignment shop in your area. Ask around, find out how's doing the best work....it won't be the dealership or Firestone!
Gary

Thanks for the response.

My only hesitation for not taking my car into the dealership for an alignment is that I believe there are sensors that need to be calibrated when the alignment is changed. Please correct me if I'm wrong.

Thanks.

exhaust rattle will most likely be heat shields.

drifting sensation is probably be tires.

my HKS rattles at 3k rpms, im thinkin bout putting some thermal tape under my bumper between the exhaust tips to quiet that crap!

My exhaust rattles to.. between 500-2k RPM it rattles.. and it SEEMS to go away after 2k RPM. I notice it also goes away after about 20 minutes of driving.. Whenever the cars cold the rattling is apparent .