Engines surges and loses power

[koolaid_kid]

I have an LT1 (I know, its not God's engine).
It was running fine, and I was getting ready to head to the track.
I decided to change the oil (silly me) prior to the trip.
When I started the engine to check the oil level, it ran fine.
I then finished filling the oil and did not start it again.
When I started it to head to the track, the idle was surging between 1200 and 900 rpm. While driving at low speeds, I could feel the surging.
At the track, it would run, but not nearly as fast as it should.
I just checked the oil level, it is slightly over full. Could this be the problem?
Or did I knock something loose while filling the oil?
Since the car ran fine prior to the oil change, I strongly suspect this was the event that caused the problem. Sounds silly to me, but it is the only thing that changed.
Any ideas?

[NinerSevenTango]

Clogged injector?

[koolaid_kid]

A valid point. I will run a bottle of injector cleaner through it tomorrow.
Thanks for the input.