What is this mystery part?

I found this rubber gasket/seal thingy today in front of my battery. It was never there before. I'm not sure if it's something that was not reinstalled when they replaced my plenum for the snapped off ACIS shaft many thousands of miles ago. Is this a gasket that needs to go back on the throttle body? Or elsewhere?

 

it looks like a intake gasket to me

 

Its the throttle body gasket. Most likely it’s the old one that was left under the hood by mistake. If there was no gasket installed, you would have lean dtcs within a day

 

Thanks you guys. Does it go on the front or the rear of the throttle body? I still want to take it apart, and check if one is there.

 

Im sure its in there or you would be getting a check engine light...you can easily tell if its in there by that piece sticking off the o'ring

 

It goes in between the throttle body and plenum. You see the little ‘leg’ on the gasket? That fits into a notch on the plenum. You will be able to see that sticking out without have to take anything apart

 

Thank you! Saves me the headache of dissembling it then. I'm going to go out and look now...

 

I see the little "nub" sticking up between the throttle body and the plenum. So there is a gasket reinstalled for sure. Appreciate the info. Thanks!

 

Glad to help