The clank is actually caused by the misfire. I had the exact same thing when I was stock.

 

Ive got brand new plugs in it. I think my injectors are dirty...U think the timing is off?

 

A stock VQ35 has a slight misfire at idle. Mine did it from the day I drove it off the lot. It went away after I went twin turbo (go figure lol).

 

Guys, It looks like a few of you have this question and though I don't see anyone referencing our parts in this thread I thought it may help to get some insight from a manufacture. When you replace the stock dual-mass flywheel with a lightened (non-dampened) flywheel you are going to hear what is commonly refered to as "gear noise" or "gear lash".

This sound, which is actually better understood as harmonics or vibration, originates in the transmission and occurs as a result of the inter-play of the gear set and the lay-shaft gear. This sound is typically dampened by the OE dual-mass flywheel and without it the sound will be more evident especially under high-load (as one would see at low RPM and high throttle opening).

This should does not evidnece an issue with the parts or the transmission and is in fact normal when dampening is removed. That being said you can always opt to use the OE duall-mass flywheel or an aftermarket steel replacement flywheel which will both provide greater noise supression. I hope this info helps. Please let me know if you have any further questions. Thanks,