Running BFG tires will not cause DW, providing they (as any tire brand) are properly balanced and don't have a defect or other sort of problem. Next, they severely overinflated your tires... 40 psi is way too high for any size tire that could be mounted on a Wrangler TJ. I would start checking for things like a trackbar that is so loose it moves when you turn the steering wheel or something else that is loose or worn. Have a friend turn the steering wheel while you watch the front-end for unwanted movement at the trackbar (especially its passenger-side mount) and the rest of the front-end.
Also make sure your toe-in is set properly. An improper/bad toe-in setting can encourage DW. PM me if you have more questions instead of making profile comments please.