dbl dz

We bought a stock 2000 XJ it drove great. We just put on a 4 1/2 inch Rough Country lift. After we got done putting the lift on we took it out for a spin and it now had the dreaded DEATH WOBBLE. Have checked the toe in, castor angle was corrected by RC, added adjustable upper control arms which corrected the castor angle to 5 degrees. Everything is torqued to specs. Took it out today after we put on the adjustable upper control arms and got it up to 70 with no death wobble, we thought that it was fixed. Took it on the highway and hit some uneven pavement and it went into the death wobble again. We don't know what else to do, or what else to check. Any help would be greatly appreciated.