Last year I lifted my 2003 Excursion. 6" pro comp front springs and 4 shocks. Zone off road rear lift with new front track bar and poly bushings. 315-75-15 Firestone Destination AT. Had everything aligned in the shop where I work. The issue is: every once in a while it feels like something major is shifting under the truck. I have checked and re-checked and cannot find anything loose or broken. I will be driving it to OBX in September and I would like to have this fixed before then. Any help appreciated.