bhsballer76

Ok. Heres the issue. The way im calculatiing it im getting about 16 mpg Highway. I have a 2000 GT . I bought the car about six monthes ago and the only mods from what i can tell are a set of flowmaster 40's and a bbk fenderwell cold air intake. The car also has SVT wheels from i belive 2003 and 275-40-17 tires. Its a 5 speed and i took the bad mileage thinking it was the result of a v-8 car (previously drove a V-6 S-10 extreme and after that a supercharged v-6 in a pontiac grand prix). I just read in a previous post that most mustang drivers are getting 18 plus city and 20 plus highway. The best i have ever gotten was 260 miles out of a tank and that was shifting before 2000 rpm everytime. My math says that in a 15.4 gallon tank, IM only getting 16.8 mpg. Most of the time im around 14-15 mpg. I drive 30 miles round trip interstate each day and and at the most 5 miles city round trip when im off the interstate. Can anyone give me some clues as to what is wrong with the car. I didnt buy the car for gas milage and i plan on horsepower mods in the next year or two , but im in school and in the mean time wouldnt mind some better gas mileage. Any suggestions?

geetee03

tire pressure at 35psi?

1BAD3V

Is the gas tank really 15.4 gallons? If so than I avg between 11.6-14.2 mpg. I usually fill up after the light comes on and about 10 more miles of driving, then it stops filling up after about 13.5 gallons, the thing stops putting gas in my car and I pump another dollar or so in, but I've never gotten 15.4 gallons in the car, its usually between 13-13.5 when I'm on empty and fill up. So that would ultimately put me between 13-16 mpg, and my only mods are k&n air filter, o/r h-pipe and flowmaster mufflers. Shouldnt I be getting more?

04BlueGT

Way too low even if you hammer it at every stop light/sign. Here's a way to figure mileage.

1) Fill up normally, either until the pump automatically stops or top off, whichever you prefer.

2) Reset trip odometer.

3) Drive as you normally do, at least half a tank.

4) Fill up normally.

5) Read trip odometer

6) Divide trip mileage by number of gallons.

If you're doing it any other way, you're probably getting bad numbers. If your mileage is still 16 hwy using this method, then you have issues. You may have bad plugs, O2 sensors, or the car may have had a tune on it. I'm sure there are other causes. Also, you should run 87 or 89 octane. 91/93 does nothing for you based on your listed mods.

04BlueGT

The light comes on when you have about 2 gallons left, so 13 - 13.5 is about right. Yes, you're mileage should be better.

Tapeuup

yeah no $hit! Is your engine missing, vacuum leak, needs plugs etc? either you need a serious tune up or your calculating wrong. do you calculate as 04 stated.

02 JRClassic

Check to make sure fuel pump and fuel filter are both in tip top shape. Both of these illforgotten parts can cause serious mpg decline

Js 99 GT

What you are saying is that you drove your car out of gas, then calculated the MPG, which would be correct if you did that, AND the tank was EXACTLY 15.4 gallons. However, I seriously doubt this happened. 04 gave the correct, and easier i might add, way to fugure it out.

Miliock

I've never gotten more than 13.2 gallons in.....and that was the time I ran a race with a buddy as the low fuel light came on

dubarado

I have a diablosport tune CAI, magnapacks and low tire pressure, and managed to get around 300 miles to the tank in my 2004.... it was all highway from norfolk VA to my house in jersey (took 5 hours) and my speeds ranged from 55 to about 110 (only for a lil on the turnpike) and even at that i still got damn good gas for an auto...