Hello all! New here and I have a question about switching oil. I have a 02 Ranger with the 2.3L, and it's a 5 speed. I currently use castrol conventional 5w-20 and a puralator filter. I change my oil every 5k miles and it always comes out pretty clean. The truck has 167k miles, is my daily putter (roughly 60 miles a day mainly highway) and runs great with no leaks/mechanical problems. I average 28mpg. I want to know if switching to a synthetic oil or a lower viscosity would help at all with fuel economy? My goal is to get the best fuel economy as possible per fluids. I baby my truck (for the most part) and coast as much as possible. I read a few threads on PPPP oil and wondered if that would be a good choice? Any and all help is greatly appreciated. I also am going to be switching my trans and diff soon to Red line fluids per threads I read.