my 99 L has been doing this for a while, the truck pulls hard to the right and sometimes to the left. it feels like the truck is throwing you around when your on a bad road. is it the alignment or something else? would a new suspension help?

 

Alignment. Mine used to "wander" also. Had the alignment done and found out it was towed out 3/8" from the factory. Set the tow at 1/16" in and it tracks straight and true.