had a similar prob with mine think it had a stuck valve in the trans case like a nutral safety switch was stuck was weird ran thru the gears then shifted thru the trans case and heard a pop in the trans then all worked great and has every since !!!
My 90 gets about 13 per gal around town with 33s on it hwy i get about 18 i dont ***** its my daily driver and it is what it is . little truck big tires gutless eng what more could a guy ask for out of his toy :hatsoff: