i dont know aboot the limp mode as i have a manual trans. is it the spacer kit? if so, the bump could be caused by the uca hitting the coil spring tower. look near the front of the bucket for a place where the arm will contact it. you should see a definate mark where it has contacted. if thats the cause, go to your local parts depot and get some energy suspension bump stops. dont recall the part#, but theyre about 3/4 inch thick. kinda domed shape an have a stud built in. youll have to drill out a hole on the uca. its there, youll see it. then fenangle the nut in there and tighten