http://youtu.be/vHVWegNfQl0   edit replaced link with embeded window

I have an 86 Quest, the car idles around 1k, but after driving and stopped at a light it will go up and down like I was hitting the pedal?? It will stop after a while but seems odd to me. Any idea what to check?? Seems like a rough idle not sure if anyone else had this issue.

http://i204.photobucket.com/albums/bb148/4cylfury/20140222_130102_zpsc0a8e60f.jpg

One was so rusted I could not get it out and destroyed it when I took out my crossmember.I need 1 at least even if its junk.I only really need the outer shell.LMK thx gig out