My guess is the pivots. Have you ever serviced the bearings? What kind of conditions do you ride in?
Most likley pull out the pivot bolts, clean everything real good, pop the dust seals on the bearings, repack with grease, lock tite the bolts and reassemble.
For some reason, the enduro bearings bleed out their grease relatively quickly and easily. In my opinion if you want your bike feeling smooth and new they need to be repacked at least every 6 months, possibly more often. And thats riding in SoCal weather, no rain, no mud.