went mudding a while back in the geo and went to cleanoff at the car wash ,a miss started, then got worse ,i changed every thing from fuel pump to fuel filter to all plugs and wires to rotor all of it ,retimed it ,new timing belt,ground straps, cut the whole exuast off from the manifold back ,new exuast with out cat,then gave up ,6 months later friends pathfinder did the same thing, found out my plug wires were cheap as hell ,spent $15 more on plug wires .fixed it, crazyest thing i ever seen now runs like a champ