2010 Hyundai Santa Fe Question: Why has my mpg dropped so much? I'm using the same gas, dealers, same driving.
I have a 2 yr old Hyundai Santa Fe. Up to the last 6 mos., I got 26 to 28 mpg (higher for longer trips). Now I am getting 20 to 23. Regular oil changes, air/fuel filter changes per requirements. Is there an additive that will actually work and help improve mpg?