clunk/pop right after start up

Hey I have a strange issue with my 2013 4cyl auto. I've only noticed it every once in a while, but right after start up (after sitting for hours), ill hear a faint, but noticeable pop (almost sounds like a clunking sound) literally about 10 seconds after the motor turns over. Havent put my foot on the brakes, not on an incline, nor have i even touched the gear lever to shift into gear. I know its not the emissions control deal that sounds like a BOV almost because illstill hear that after about a minute or so of it running (as its always been).

Any ideas? I plan on asking the dealership about it, but since its not every time i highly doubt theyll be much help.

 

I should add it sounds like its comming from either closer to the fire wall or right by transmission.

 

Bump. No ideas?

Ive tried searching the forums, but nothing similar seems to come up.

 

My 4 cyl does this too mosty when it's warm out. I believe it's just a slight pop out of the exhaust cause from the higher startup rpm then dropping to idle. When I put the aftermarket axhaust on it became more clear sounding it also does it when I left off the gas to shift. I don't deal like it's anything to be concerned about.

 

Engine air pump

 

Experience this on my 4cyl auto also. Intermittent startup pop. Can't predict when it's going to happen. It's not the air pump.

 

Check the heat shields on the cat aren't loose and hitting something