I have found that the 2.5's tend to leak around the timing cover. the oil leaks onto the right side crossmember near the lower control arm and puddles up in that area. It mixes with the road dirt and just clings to the frame .. but 3-4 qts would be hard to miss. pull your spark plugs and examine the electrodes to see if you are burning oil

99 SE 2.5 DuraTec , Mtx and faster than a speeding bullet "Modified? this little 6 cyl? Dont be upset because I beat you!"