Low MPG in 2014 Mustang GT
 

I purchased a 2014 Mustang GT Convertible, 6 speed manual transmission, 5.0 in October of last year. I have since then put about 11k miles on it and gotten the oil changed every 5k as recommended by ford. When I first got this car and up until about a month ago I had been getting 330+ miles per tank and 22-28mpg. Out of nowhere the mpg dropped to about 12mpg and about 220 miles per tank. Is this normal? I've tried resetting the gauge after filling up a few times and it hasn't changed. Is there anything I should do to it? I've only had the car six months and driven 11k miles total.

12 mpg sounds really low especially if your driving style hasn't changed. When I first got mine I was babying it, Now I've been driving pretty agressively, but still average about 21 mpg on a tank. Try a long stretch of highway at 70mph to see if you're up in the mid 20s. And you don't need to change the oil every 5k, they have an intelligent oil life monitor that calculates when you need to change it based on the conditions and driving style. I got 8700 miles out the factory oil. In general though, when you see a huge drop in fuel economy, it's a bad MAF or 02 sensor. So if the problem persists and no type of driving changes lead to an increase in mpg, you should have the dealer look at it.

I have an 07 GT vert, 45,000 miles and get 12-14 MPG. I do all local, stop and go driving though so it's about what I expect to get.
I have tested hwy driving and the MPG jumps up to low 20s.

My first tank since buying my car just a week ago was around 12mpg and 220 miles on tha tank as well. Of course, I drive me car hard, did almost all city type driving, and it had 87 octane in it. This time I put 93 in it, and have been driving it much nicer, so will see how it goes.

There are so many things that factor in to your mpg, it can be hard to pinpoint. Quality of fuel, octane, slight change in driving conditions or habits, faulty emissions equipment, how many passengers you have (weight)....

Oh octane myths, will you ever go away?

yeah mine has been about 15-17 mpg. but i do lots of city driving. not much hwy driving except 10 miles here or there. and i drive it like i stole it

I'll try driving on the highway and see. Up here I do a lot of driving on post which is 35 mph tops and a lot of slowing down/stopping. Luckily it will be nice this weekend so I'll take her for a spin. Thanks for the feedback. If it is anything with the car, it will be covered under warranty.

Ya get that Horse on the hwy, reset the MPG right as you get on there and see what you get. If it's below 20 for that stretch then you might look into what's up.

I get 23mpg in my fox on the highway and about 15 in town... IF I stay out of the throttle . I can suck the tank down to empty pretty quick though if I do a lot of hard aggressive driving.

getting around 20 mpg in my 14 6 speed around town on hwy can get 25+