Okay, i cant really expalain my question, i can only give you an example of what im talking about and see what you think. So, here goes.
As you may know i have my "tacky" vacuume gauge that reads from 30-0 clockwize.
Say im driivng at 45mph in "D" and the gauge is at 10. Now i can be driving at 45mph in "3" and the gauge is at 19? Am i saving gas by keeping the gearshift in 3?? I know the engine is running faster, but ive been told that the higher the number on the gauge, the more gas im saving.
The same is true if im driving in "D" at about 30mph, the gauge is at about 13. But if im in "2" driving at 30mph the gauge reads at 22?? Am i saving gas by keeping the car in a lower gear even though the engine is running faster??
Please help, im driving alot of miles a day and im wanting to start saving some gas.
Thanks all.

 

Overdrive forces you to shift into the highest gear possible as fast as possible, that helps with your gas mileage by keeping the RPMs down.

If you want to save gas, just keep the car in OD and keep your RPMs as low as you can.

 

No, absolutely NOT, you are using more gas by forcing your car to stay in a lower gear. The factory made it so your car could shift into higher gears at the speeds they did specifically to save on fuel. If you got better MPG in 3rd at 45, then the factory would have raised the shift point so that your car was in 3rd at 45, even if the shifter lever was in D. Think about it, the factory wants MAX fuel economy out of their cars too, this gives them an edge in corporate fuel economy based on their EPA estimates.

Like Chibi said, for the best gas mileage, drive your car easy, try and keep the RPM's low, accelerate gently. And ALWAYS just keep it in "D," this will allow your car to shift into 4th (OD) as soon as possible, and save on fuel.

 

alright thanks, thats pretty much what i was thinking. was just a little confused. thatnks for the clarificaiton.