Welcome aboard. Your problem could be a lot of things. Check your caster angle first. A lot of bolt-on mods to the suspension (shackle lifts, etc) aren't careful about that, and it's vital to good handling. How's the ride? A rig with leaf springs at all corners is going to be rough, but it shouldn't be violently rough. Mine came to me with an aftermarket set of lifted springs that were so stiff the shocks never had a chance to do anything. It was brutal.
You'll see much discussion about the YJ's track bars. They were installed to appease lawyers since the narrower CJs had a bad reputation for flipping over in corners. If your suspension is bone stock and you don't want to mess with them, they're not causing any problems... but they aren't doing a thing to help you either. If there's any suspension lift on the rig at all you should consider removing them. The extension brackets they add to lift kits to make the track bars work like to break a lot.
Cheap or old tires can be a factor on these rigs. The rest of the suspension is so crude that tires play a big part in how the rig handles.
Some things to look for while it's on the lift: Shock mounts. The rear lowers like to break for some reason, and depending on where you're at, rust can be an issue. Spring bushings, and play in the steering linkage of course. Track bar mounts as I mentioned above. Sway bar mounts up front. The YJ's suspension is pretty simple. Body mounts. If they're worn it can really effect the perception from the drivers seat. Mine came with a body lift and worn out bushings. When I went back to new, stock mounts it improved the feel of the rig a lot.
Do keep in mind that this is an old Wrangler. Next to pretty much any sedan or modern pickup handling is going to suck. If you don't have vibration and the thing tracks straight, you're ahead of a lot of YJ owners.
