What a difference a battery can make ! I changed out my OEM battery last night. (Walmart Everstart brand group 51r $75.00). I have driven 60.1 miles. 12 on country roads with 7 stops the other 48 on highway mostly 65-75 mph
cruise control. 42.2 mpg. That is my best ever. I usually hovered around 36 to 38mpg. I obviously make no attempt to maximize my mileage. I just get in and drive. I can tell you one thing for sure. Don't believe the sightglass.