Something wierd that just popped up on a new G35 AT with only 800 miles on it. When I start it up, put it in drive and go forward for the first 100 feet or so (under 1500rpm), it sounds like traprock is hitting the underbody beneath my seat and then I hear a muffled rattle somewhere right behind the engine it seems. It only happens from a cold start. I can't repeat it again after the engine is running.

Has anyone else run into this?

BTW: It happens when I am in full automatic mode or "manual" mode.

 

Does it happen right about the time you first get up to 7mph? It's the ABS self-test cycling the brakes. It does this every time you start the car. If your foot is on the brake pedal when it happens, you can really feel it (easier to accomplish if you're parked on a downhill incline).

 

I don't think that's it. I've heard that noise seconds after I turn on the ignition. This is a different type of sound - first it sounds like trap rock hitting the bottom center of the car (like a stone or two) followed by a mufled rattle. The sound occurs very quickly. I can repeat it every time. Guess I need to see the dealer.

 

You were right. I stopped at my Infiniti dealer this morning and their lead tech went for a ride with me. The sounds that he heard were coming from the ABS doing a self test. I don't know why I never noticed this before. It's a strange sound, but he indicated that it's typcial for Infiniti's. Thanks for pointing me in the right direction!

 

wow----i always heard that too and wondered what it was---i thought i was just worrying to much about things--lol--glad to have an answer!

i love my g'izzle