name that sound!

got a 02 sr5 4cyl 5spd 4wd with 33'mud terrains and a toytec 3'' lift with the aal and coilover spacer, i also installed the diff drop kit..Im pretty used to alot of road noise from the tires but a new noise arose recently..once i get over about 35 mph a rythmic sound starts coming from what i believe is the front passenger tire. sounds like vhhummmp vhhummp vhhummmp...you get the idea. when i go faster the sounds are more frequent and louder. i jacked up the passenger front tire and spun the wheel an it felt very normal and i shook the tire in all directions and didnt really feel any play..im sure i didnt really check anything but it seemed like a good idea at the time. anyone have any idea or have an idea or know what to check? thanks a lot