3.8 V6

[Gearbanger 101]

I get about 26mpg in my 4.6L Supercharged Cougar if I'm careful....and its tipping the scales at over 4,000lbs with me in it.

The 4.6L's are generally better on gas than the 5.0L, but only by a couple MPG generally. Driving style has a lot to do with it. Every time you jump on it out of the hole, or whip out and pass a car, you're killing your mileage.

The 3.8L's are generally underpowered, so they expel a lot of energy trying to get the car moving from a halt....which in the end often doesn't make them any better on fuel. The split port engines although more powerful, don't make a whole lot more torque down low. Ford was able to increase the amount of air moving through the engine, but as a result additional fuel is need mileage suffers. Although I will say my old clam shell intake 150hp 3.8L Cougar with 3.08 gears got great highway mileage. Went through two head gaskets though.

 

[Mustang5L5]

thats the thing I don't understand, my lil bro has a got a supercharged 98 converible and was getting around 30mpg, without his foot in it. People with bone stockers are getting like 18, I get 24 in my 92 GT with an auto in it, wassup with that?

Driving style mostly.

I've had days where i've gotten 10MPG....and then days on the highway where i've done 27MPG

Shifting a little sooner or taking your foot out of it a bit makes a huge difference.

 

[Stang2Man]

When I still had my 2004 GT with a 5spd I was able to pull down 26mpg shifting at 2k RPM each shift. I'm still kicking myself trading it in for an Expedition

 

[The Flex]

As Brian said, torque is the key. Torque is what gets the car moving, not horsepower. The more torque an engine makes, the quicker it will come out of the hole in drags and the better the economy on the streets. This is why supercharged engines can be fuel efficient. The supercharger doesn't just add hp but a lot of torque as well. Take the SC version of the 3.8. The addition of the M90 added 70 hp over the N/A 3.8 but also added 110 ft/lbs of torque.