Check Oil Light & Knocking

My check oil light came on last week and when I checked the oil level was right at the bottom of the dipstick. I topped it up but the oil light never went off and know I get a knocking in the bottom end at idle. Almost sounds like there's a small piece of metal in the exhaust. When I bring up the revs you can't hear it.

Do you think it's a spun bearing?

Any ideas about the oil light staying on? The level is good now...

I'm going to the racetrack tomorrow so we'll see if she lets go

Forgot to mention that the oil pressure and engine temps seem normal.

I can't hear the noise from the top of the engine, only from underneath the car. I originally thought it might be a loose heat shield on the exhaust but i shook it and hit it with a mallet and it's solid.

Wow, I can't believe I posted this back in 2011... I haven't driven the car much the last two years apparently.

I had some issues with the daily driver so I had to take the fox to work this week. The problem is still occurring. It sounds like a metallic knocking sound coming from underneath the car. It only seems to do it when I am engine braking at low rpm ~2000-2500. When the car isn't moving I have a hard time getting it to make any noise. I haven't really been concerned with it since I have another engine on a stand waiting for HCI if I ever get around to it but it's annoying me this week since I'm driving it to work lol