08 G37S Coupe.
It usually made a clicking sound when I turned it off, but now when the car is in drive and only in drive does this happen, it makes a rapid non stop clicking sound, but as soon as it's in neutral it stops. What is it?

 

It's more of a ticking sound, like a clock but rapidly. Can this be because I've used 87 octane?

 

Pretty sure you posted this in the wrong category ask a mod to move it to the correct one for better and more responses. As for your situation any chance you'd be able to upload a video of the actual sound, bc by the sounds of it, it can be a couple things.