When I first bought the jeep I had an issue with taking off in first after then engine warmed up. Also, the oil pressure would bottom out to zero so if I was stuck at a light I had to rev the engine to bring pressure up but it would still take off rough unless I slowly let clutch out with high rpms. So...I changed oil, replaced oil sending unit, and finally the oil pump. Oil pressures great, and rough take off doesn't happen often or nearly as bad. However it still does shake bad at times from 1st gear. Also noticed its getting tough to get passed 60 at times. Ideas? 1997 tj sport 4.0. Thanks group!