It does sound like a bad tire or wheel, at least one of them sounds out of round. Find someone with a Hunter GSP 9700 Road Force
tire balancer, this is the best piece of equipment for balancing tires. Ask for match-mounting, especially if you know what 1 wheel/tire combo is bad. This should do the trick


99 Silver SVT with:
lowered-eibach springs, piaa fog lights in upper mesh grill, K&N filter, tinted, flowmaster mufflers, straight-piped cat(temporarily w/ca. for emissions), custom spoiler