Originally Posted by Shmoo

Not if you have to floor it to accelerate.

Say you shift at 2k...imagine how much throttle it requires to get up to speed. Now, if you shift at 4.5k like I do at a 20% throttle position, you are using less gas and accelerating faster.

Now if you are cruising, 60mph in 3rd is wasting gas, so 5th would be a better choice.