do we get better gas at higher RPM's or higher gears? cuz it feels that when im at like 4grand in 4th my car is perfect, but 5th feels like its struggling

 

Even though your post makes very little sense I will try and help. Better Gas? Gas quality does not change based on gearing.. Are you referring to gas mileage? Gas economy is a equilibrium if you lug your car its going to not run efficiently but the top gear will be the most efficient at the right speed.