I recently got headers installed on my car and now when it's started it will run but as soon as it idles down it just dies. Help?

 

Video of what's happening.
https://www.facebook.com/photo.php?v...type=2&theater

 

After unplugging the negative cable like Andrew Kochman said. Then after starting it a few times and it slowly idling longer each time it finally stayed running. I drove it around town a bit and had to stop for two long trains. The only time it stalled was when I pulled to a stop at a roundabout. It definitely ran rough and I'll be messing with the timing here soon but hopefully it keeps running enough that I can use my car.