Help! ok ok, I've read all the posts and still am not sure of an answer. Does a 93 LS400 have a cabin filter? And if so, do you know where to get one other than the $$$dealer. Have checked most if not all internet sites and no one lists a cabin filter for a 93 LS.
It may be transmission shudder. I had what seemed to be a similar problem, changed the trans filter and problem went away. Came back after about 60,000 miles, changed again, problem went away again.