I know this might be a dumb question but I cant get an answer unless I ask. My truck is a 94 k1500 z71 and I cant for the life of me figure out what rear end is in it? also I have noticed a substantial loss of power going up steep inclines and an even greater loss of fuel economy over the last month, changed the plugs, wires, cap/rotor, and injectors. thinking it might be a vacuume issue but ive been known to be wrong before. Any ideas before I start dumping money into it that I might not have to?