idles bad when it warms up

[88mustang lx]

it runs fine when you first start it up and when it warms up it idles ruff but when it completly warms up idles fine again what could be causing that?

 

[SSChris NY.]

Check the gap on your spark plugs, replace your the Spark plugs if need be, Check the cables as well, if that dosen't do the trick, Check your AIC on the side of your TB, that's the big cylindrical sensor