Not sure What the problem but with 100k it'd wouldn't hurt to change the shocks. A guy at the local 4x4 store here owns a 97 and just replaced the shocks with some made by Edelbrock and he says they are awesome. He put a set on another customer's Expedition and they guy says he now takes the off ramps without slowing down! The vehicle stays dead flat! With 1,680 miles on mine the "softness" of the factory shocks is the only real complaint I have! I'm going to be upgrading to the Edelbrocks some time in the next year. Good Luck!
2002 XLT with Sport package, Comfort/convenience, 5.4L, Leather interior, Moonroof, tow package, 3.55 Limited slip, side airbags, rear sensing, CD changer. Mods Front tinted windows, Husky MudFlaps, Lund interceptor Bug/stone shield, Advent window vents. And of course Zaino and more Zaino