There's a few steps I'd take.
Weigh the front and rear. Post the weights for review and tire pressure suggestions.
Aligment: check recent thread on alignment specs review. Caster settings within the spec can make a difference-they should be set toward the 7 degrees positive. There should be slight toe in (not zero or tow out).
I found the heavier sway bars from Roadmaster made it feel more buttoned down.
I'd have the suspension checked by reputable outfit for any looseness in steering gear or linkage.
Somewhere in all of the above you should find improvement.