Couple days ago when i was reversing into my house i pressed the gas pedal a little too quick and sharply. I heard a sound coming from the engine which sounds like a piece of metal clanking against something. I can do it on command as well. it only does it in neutral or parked... I attached a video of the sound here.

 

Your video is private. Likely a heat shield or something though.

 

video is viewable now.

 

^^^^^what he said. check the shields on the cats and the headers.Cats especially are notorious for rusting around bolts and rattling. I live in a rust prone area and found a rattle from a plate on a harmonic balance near the tranny that had rusted and dislodged...rattled between 2800-3600 rpm on cue drove me nuts

 

Does not sound good at all. No idea what it could be but scares me.

 

I was just able to play the video....forget what I said earlier...l've never heard anything like that before. Hopefully someone else can help. GL.

 

Heat shield?? I don't think so. A heat shield would be more of a rattle.

My first guess would be the AC compressor clutch. Is the ac on? If so turn off and repeat.

Take a bright flashlight and follow the belt while someone else revs the engine. Observe the pulleys (or as many of them as you can).

 

Damn man that sounds bad I really hope it isn't anything serious

 

Are you quickly flooring it at idle?
If so, what happens if you increase engine speed slowly from idle to 2,000 rpm and then floor it?
Do you hear any knocking when driving that car?

 

It does it when the ac is off as well. I did tried to pinpoint the noise by using a bar and putting it on various spots. I tried pulleys but no go. I mean, you can hear the noise through a pulley but it's not that loud. The noise seems to the loudest when i put it on the front valve timing cover on the right... There's no codes being thrown though. I'm really hoping this is not an engine problem.

 

It could very well be internal to the engine too. Maybe something binding up in the VVEL.

Still under powertrain or extended warranty?

 

72 months correct? Mine's is a 2012.

 

Yeah, maybe some bad gas as it sounds like "knock".

 

Yes, 72 months.

@sonicvq, you think it's detonation? I can't remember the last time i heard engine knock in a late model car. In older cars it sounded like marbles rattling in a can.

 

I would do, is contact someone at your local Infiniti dealership and make an appointment. What ever is going on with your engine it's a noise that should be looked at by a trained professional. Take the video and have them give it to the tech. I had a similar problem with another car and it ended up being the Cam shaft but their was a recall on it. Either way take it in ASAP