Throttle ?

[coheed]

Is it better to drive in a higher gear with more throttle or lower gear with less throttle? Maybe 500-600 RPM difference. And this doesnt have to apply to just the Yaris.

[voodoo22]

Depends on if you're going uphill or down, but if you're on a flat road you want to be in the highest gear at the lowest rpm which allows you to not put too high a load on the engine if you want the best possible efficiency.

Going uphill you need higher rpms, going down a hill you need less.

You have to go by feel. You'll know when you don't have enough rpms for what you're trying to do because the car will sound different and be unresponsive.