i just recently put the diablo sport predator tune on my 2003 Mustang GT and noticed with this tank of gas i only got 12mpg...with my stock tune i got 15 or 16...is that normal to lose that much? because i cant afford to get that kind of fuel economy. lol. thanks for the replies.

-Nick

 

Sounds like you keep the pedal to the metal with those mpg. You should get in the 20's with normal driving with a stock tune and your mods. I got the SCT by Brentspeed and it does great on fuel with normal driving but will drink it when you run it hard.

 

I can get 31 mpg with my 04 GT M5.
That's as good as it gets and is all 55 mph road driving.
It depends on the tune andI would go back to stock until you can get to a dyno.
I'v never used a handheld tuner but if you can just change timing from idle and leave the fuel trims alone that's where I'd start.I have a Steeda timing adjuster and when installed,the car picked up two mpg on the road.
I also noticed in your sig that you are planning for 4.10's.If gas mileage is a consideration you will want to think about that.Lot's of people have posted on here that their mileage went up in stop and go driving after gears.So ???????

 

no actually i babied it for the week that the gas lasted to see the max MPG i could get. i gunned it maybe once in the whole week....boring to drive like that though. so something is wrong.

 

see if your throwog any codes on your obdII. You can check that when you boot up your predator. see if your running a lean bank on your o2 sensor. How many miles on your car, it might be time for the 02 to be chnged out. Also, did you screw around with your tune. to lean/to much fuel, ect. I had a predator and when I screwed w/ the tune, my ga miliage went to ****. Wehn the tune was right though, I got 28 mpg city and about 14-16 wot.

 

well...about the 02 sensors...i turned them off because i cut out my cats. i did screw around with it, but nothing with the a/f mix. and i have 40k miles on there.

 

Did you not know HOW those programmers make more horses..?

They dump more gas into the engine...

 

maybe..but everyone i heard of that used it have better gas milage after. i just reset all the parameters so im gonna see how this tank will do.

 

in my small town with no highway driving i get about 13mpg and on the interstate doing about 95 ill get 23ish. stock tune with just CAI and exhaust.

 

well with my stock and CAI i got 15 in the city and around 23 on the highway. and now im getting close to 13 city and i dont know about highway. but i just reset all the parameters. so ill see if that helps.