If its a 4.6 its the lifters. They always do that lol. My mommas Grand Marquis does lol 145K and still going strong. I hated ASE questions when I was in school. Oh well. Ill go with Neither.
whos right side? as if you were looking at the engine? or sitting in the truck? if in the truck there both wrong. Oil filter in on left side if in truck.
Well, I don't like modulars..so I'm pissin in the wind here.....I'm gonna say neither and it has something to do with the size or location of the oil pump port.