i've had death wobble many times. once it was a bad axle bushing on the track bar, had a new one machined from uhmw.

another time, couldn't figure it out since all was brand new (long arms/johnny joints) with fresh alignment, so i threw on a brand new, wait for it... steering stabilizer with coil over. fixed.

another time was with my 36 swamper iroks, bias ply on beadlocks. but that was because i removed my stabilizer when i built my steering links. links were too large to use a stabilizer, binding against it. so i removed it, instant death wobble at 30. pulled wheels and swapped wheels with my tj. no more death wobble.

so, it could be simply your tires...

 

If all your equipment is in good condition and you've added lift. Then insure your alignment is up to snuff. Lift will require more caster dialed in. Hence longer control arms may be in your future.
If lifted, insure your toe is 1/16 to 1/8 IN. (the Peep is found sensitive to toe).