Intermittent metallic rattle after cold start

Intermittent stuff lies if you only catch it once. Swap the cheap/easy piece first on the 2013 Infiniti G37 and see if the fault moves. If the cheap test changes it, stop and reassess. On “intermittent metallic rattle after cold start,” that was the fork that mattered for me. Monthly payment math is how wallets disappear. Heat soak after errands is the other window.

OP here — recorded a short video and noted speed, temp, and whether it was in gear. Next check is the cheap one I can do in a driveway.

I wouldn't throw parts yet. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. Save the big job until that test fails. Write the result down so the next test isn't a repeat of the last one. I'd rather look cautious in this thread than stuck later.

This is usually cheaper to test than to guess. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. Save the big job until that test fails. Just my two cents from doing this recently. I refuse to clear codes until someone else sees them.