The miata has been out of the garage since May when I installed E3 spark plugs and switched to synthetic oil 0W-30. Of course I have no ABA tests, but I have (what I consider unusual) results.
My mpg has been increasing about 1 mpg per tank. The first was 39+, then 40+, 41+, and the last one was 42+. The conditions are about as equal as possible--same route, barndoor headlights open to work top down home. There are no other mods except I pumped up the tires and removed the cold air intake snorkel, but these were done before the season.
I'm afraid the oil and plugs made no difference, and I'm just becoming a better adjusted driver......any thoughts?
