ive heard you dont want to go too low either. accelerating at 1krpm after a shift, im told is not good for the bearing. If your interested enought, get a bluetooth obdII device, and buy an app called dashcommand (assuming you have a smartphone). when you enter your cars info, it gives you a reading on your fuel mileage. whether or not it is accurate, it will still give you an idea of how much fuel output is happening, and the difference in throttle at different rpms.
Theres a pretty happy medium you want to stick to when driving. its just about rpm, or just throttle, or just shift points, its about utilizing all three. in 4th gear, at 35mph cruising, it would say im getting like 19 to 21 mpg, (not positive, but relatively speaking) but if i speed up to 45mph, i would be getting a little better, like 24 to 26 (again, relatively speaking).
at the same time, if you are in overdrive, and at 1.4krpm and then pushing the gas down, you might see a drop from 26mpg to 20 mpg, but you will be at 20mpg for a long time. but if you downshift to 4th, speed up at about 12 to 15 mpg for a few seconds, then back into overdive, you will be at your desired speed faster, and back to saving gas cruising.
also make sure if you use an app, to watch your throttle percentage. (mine starts at like 16% throttle with my foot off the gas (just the reading from the tps, it wont tell me 0 even with the engine off) as you push the throttle, you see that percentage go up, and its helpful to take notice of that number, because you can train yourself to hold it at the lowest percentage to maintain speed. 1% too high will be "accelerating" but only increasing by 1mph per 5 or 6 seconds, but your fuel mileage will drop.
hope all that wasnt confusing...
once you wasted enough time trying to maximize your fuel economy using an app to train yourself to squeeze all you can out of a mustang, then you will have a better understanding of it all, and can easily go back to driving without it.
and a final note, The gas that you do save in a mustang has nothing on a little economy car. so at the end of the day, you may wanna just spend a couple extra bucks per tank and just enjoy the ride. but this can be pretty helpful for a long road trip.
2002 GT 5sp. 16x,xxx miles
Steeda Exhaust, C&L plenum, BBK Throttle Body, Steeda Underdrive, Steeda short throw, unknown stage clutch. Rear main leak. Compressor seal leak. Steeda lower control arms. good tires.