There is some kind of slipping or something in 3rd gear and it happens almost everytime, anyone have any idea what it might be? you can here it in this vid twice right before i let off, any help is appreciated

http://videos.camaroz28.com/video/21...E4E216A23B.htm

 

Sounds like a ignition or fuel problem. It sounds like its cutting out. Maybe time for a tuneup.

 

I just changed the spark plugs when i got the headers installed

 

When did it start?

 

I would bet a paycheck it's your plug wires.

 

...... or the addition of the extra power took out 3rd gear. I'd start with the plug wires though. If it started after the header install something must be toasted or not reinstalled properly. Go back and check all your wires and harness.