Truck rpms bounce while at a red light

[etnies86]

I posted something up earlier about the rough shake while reving up just below a grand rpm well I changed my fuel filters top and bottom and the oil the other day so that went away but I noticed this and it only happens once in a while but while sitting at a red light the rpms bounce up and back down a little not a lot very little enough to notice though... If I turn the truck off and restart it goes away till the next light now it doesnt always do this just sometimes so I went and replaced the batteries cause they were a little weak this morning thinking mayyyyyybeeee that had something to do with it but nope...
Any ideas?!

[etnies86]

bumppp someone has to have an IDEA

[etnies86]

Just thought of this.
It did this when I had the two weakkkkk batterys in the truck
I changed the batterys and the day I changed them I noticed the truck do it 3 more times.... Its been a few days now since I have put new batterys in and I haven't seen it doing it once...