Mob Bomber

I'm with everyone else on here. Depending on how many miles you have, it sounds like you need a good tune up and fresh fluids. IMO, sounds like you are driving around your V6 like its a highly modded V8. Ease into the throttle and brake more and see how changing your driving habits improves your mpg. My '13 GT gets me 22 average with 80% city and 20% highway.

alkemist

Make sure your tires are inflated and in top shape. If you drive highway a lot and not in tight traffic, cruise control will help with mpg.

I get 18.5 mpg on my GT with mixed driving. I have an auto so it's very easy for me to coast a lot, I don't rush to a stop light just to brake. I keep with speed but ease into the light/stop. I don't need to be the first one to sit around for a couple minutes.

Don't rely on the onboard computer, it tends to be off. Old school math is your best bet for accuracy.

The newer mustangs go with a charcoal chrome/dark grey chrome color pony. Otherwise it depends on how you are going to theme your mustang. I've even seen flaming ponies. As for myself, I went with a delete.

Keep it real

I'll see what I cant do this week and see if I can come up with some better results

Nuke

A good tune won't buy you any fuel mileage improvement unless you really have will power to drive granny style and even then, you might luck out and see about 1-2 MPG gain. At that rate, you might break-even over the cost of the tuner and tunes in about 6-8 years.

Keep it real

16.2 mpg is an average after using 3/4 of a tank and it last me a week

kput

I get 15mpg city
Have ever since I got the car, both before and after tune.

That includes both 20" wheels (36 lbs per corner), and OEM wheels (about 20 lbs per corner).

I've tried driving like a granny, but that only nets me 1-2mpgs more... and then driving just isn't any fun.

I run a 91 octane Race tune, and I drive it like it's a race car. Plenty of WOT runs, hard accelerating, etc.


So 15 is about right..
as for highway, I pulled 25 with cruise control set on 85..not to mention multiple WOT runs..

I average about 200 a tank.