well I just bought some 10w-40 high mileage oil and a quart of lucus oil leak stop stuff to thicken it up Hope this works

 

i have a 93' with the 3.9, sounds reall close to what mine was doing.
i had to change the oil pump (worst case scenerio) due to a clogged oil pump screen. sometimes the screen gets clogged and doest allow enough oil to get through. i had to get the engine pulled to get the pump changed.

 

well changed the oil today and it seemed to help alot the oil light never came on so we'll see if it does when I drive alittle farther