what the heck!!

[kal2005]

So i was driving my truck home from work tonight and i noticed that once the truck accelerated up to 110 km/h and let off the throttle to maintain 110 the truck started making a nudging/bumpy feeling and it wasnt road conditions because when i speed up it goes away. I am wondering if this could be alignment or balancing issues or if i should be looking into bigger problems. i know its pretty minimal info guys but i got no codes and tires that have been sitting for a while that have ballancing beads not weights. Any help would be greatly appreciated because i love this 6L