2000 Silverado 1500 - Starts but won't idle (with video link)

Hi Guys,

I'm new here and hope someone might have an answer or a direction for me to look towards. I'm going to try and give as much detail as I can here.

Problem:
Without Gas Pedal Pressed - Truck turns over, starts up, and dies (no idle)
With Gas Pedal Pressed - Truck turns over, starts up, and runs (will not idle without fuel)

Here is a link to a video I took with my phone to show my brother (I wondered if he had any idea at the time)
https://app.box.com/s/8hxq9iwiml1cg04ysjg2tm2mcxwd849i

What I was doing before issue occurred:
Truck ran great and then I:
-- Project 1  (replace windshield fluid pump) --
1) Disconnected Battery
2) Disconnected Front Drivers Side Headlight unit
3) Removed Windshield Fluid Pump from reservoir
4) Disconnected pump wiring
5) Connected new pump to wiring
6) Reinstalled pump into reservior

-- Project 2   (replace side mirror switch inside drivers side panel)
1) Removed interior unit from door
2) Removed old mirror switch
3) Inserted new mirror switch
4) Replaced interior unit into door

Finally:
1) Reconnected Battery
  - here is where it might have caused issue with something -
2) Ignition key was left in ACC on accident
3) When reconnecting battery the electrical would come on and off as I was trying to screw in the terminals
4) tightened terminals and tested truck which would not idle afterwards.

Side notes: mirror switch now moves side mirrors left and right, lights come on, door dings, everything appears to work.

I have looked at fuses in the panel and don't see any blown fuses.

Anybody know what I can do to fix it?
Thank you in advance for looking at my problem.