Could be any number of things - as far as fuel economy for a 5-speed 7th gen - those are about ballpark. Might be differences in fluids and tire pressure/tire construction. On my 2002 Corolla 4-speed - I noticed an immediate 5+ MPG increase by adjusting tire pressures from the recommended 30 PSI to 40 PSI on the OEM Goodyears. Not all tires are the same, some like the extra air, some do not. Might need some experimentation to find what works best with this particular car.
What are your numbers?
With 30psi.. I feel every bump.. with 40... I don't know.. Is that recommended? I will check the limit for my particular tires..
All fluids in my car are new.
TRCar54 makes a good point with the current weather being a potential part in lower fuel economy. Same deal with many places running oxygenated gasoline for the winter time. Less energy content - so you get less MPG.
I generally run mid to upper 40 PSI, even touching 50 PSI for tire pressures in my cars - I think I have a post somewhere on here where I list specific pressures. Really helps even out the treadwear on the tires - as these tires tend to wear out quickly on the edges.
EDIT: Found it here. https://www.corolland.com/forums/index.php?...st&p=149935
As for tire pressure - depends on the tires and suspension. Some tires like lower tire pressure, some do not. Since I do more highway driving, the higher pressure makes more sense for me. Most tire specialists recommend adjusting the tire pressures in 2 PSI increments until you find a pressure that works for you comfort, noise, and performance wise. More tire pressure generally will sharpen your steering, keep the tire carcass from distorting at speed, and generally maximizes fuel economy and tire life. There are drawbacks and a limit to how high you can go, too much pressure will cause the tire to wear more in the middle than the edges, reduces absolute traction, and can increase braking distances.
There is no set tire pressure that applies to every car - I like to treat the tires pressure located on the placard and the max cold inflation stamped on the tire itself as numbers to bracket my "correct" tire pressures. I start at max cold inflation (don't worry, tire will not blow up) and bleed the tire down until I get a good compromise in performance. Used to work R&D for a major tire manufacturer - road testing and lab testing almost all aspects of tires. You'd be quite suprised to know what tires are capable and not capable of.