Right when my engine turns over I feel a thump or thud or clunk coming from directly behind the clutch pedal. Engine starts every time, just hear and feel this quick thud. Anyone have an idea of what this could be?

 

Is it loud and does it sound bad? Hard to say but if you upload a video it might make it easier for us to find out what could it be.

 

This is fairly common on our cars.

The timing chain system is hydraulic, so it takes a second for the oil to circulate and tighten up the tensioners. I believe the sound you hear are the chains themselves during the tensioning process.

Here's a good thread that discusses the issue: cold knock on start up

 

It seems like the engine jerks really quick right as the starter engages. I've heard the rattle discussed in the thread when I need an oil change, this is a different sound. The video I shot doesn't show anything. You have to have your foot on the clutch to feel the thump. Feels like the firewall is loose.

 

Could it be a motor mount?

 

That's what I'm thinking, but I looked at the engine mounts and they are not cracked or leaking. I feel vibrations through the gas pedal while driving so I'm very close to bringing it to Infiniti for them to look at it.