I have a 3.0 duratec ford escape with cd4e transmission. 165,000 miles. I switched back and forth between amsoil synethic and walmart supertech conventional and noticed getting fewer miles to the tank with the synthetic oil. What the heck!? any reasoning for this? I get about 30 miles less to the tank with the amsoil vs. the cheapo walmart oil. same weight, 5w20. same route driving too. i don't use a/c.
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