Horrible Gas Mileage! I need help!

[88Saleen544]

I am running a CAI and 89 octane tune from Brenspeed and I average about 16 miles per gallon. I drive 8 miles each way to work and back, 7 of which are highway miles. I don't really goose it all and drive somewhat conservatively. One trip, when I first got the car I took it on a trip and got 25 mpgs, but can't recreate anything close to that. It actually got worse after the tune, but the dealer I bought it from (its an 06, I bought used with 13k on it) had swapped out the original tires and wheels for 18" ford rims. I wonder if they corrected the computer and I am waiting to hear from them on that. Otherwise I am going to have to check the fuel filter and spark plugs and hope thats the issue.

 

[stanmckinney]

The EPA ratings are something like 17 city and 24 highway. They, in my opinion, are always high. Though many will disagree and claim they get more, I think if you are getting 16 in mostly stop and go driving you are doing OK.

 

[CRoberts91]

i didn't see you mention anything about the oil. you changed it lately?

 

[Blak05GT]

The oil was changed about 500 miles ago so it can't be that. It was getting bad mileage before and after the oil change. For those of you who have tuned your car what do you recommend that I use, the DiabloSport Predator or SCT Xcalibrator? Those are the ones I'm looking at getting. Will one work better with my MMR intake? I'm looking to get some better mileage from the tuner. Are they pretty easy to use in your own garage or do they require a shop to figure out the tuning?

 

[SlideWRX]

A lot of my driving is in town. It's about 4 miles to work and 4 miles back. That with a stop or two at Wal-Mart usually gives me 13.4 miles per gallon. I can't get any better no matter how hard I try.
On the road I have gotten as much as 28 miles per gallon.

The short trips are a big part of it; My car often takes ~4 miles to get to operating temp, so you are running the engine cold a lot. If you've gotten 28 on the highway, then it is definitey the short to/from work trips.

Tom

 

[JimsWhiteGT]

I'm getting 18 city on 87 octane and stock tune. Around 26 highway at 75 using cruise control.

 

[RagtopV8]

I got an even 27 mpg on my way to work this morning, according to the info display. My commute is 35 miles one way at 65 - 70 mph, low traffic. That's better than I expected.

 

[scottfree]

i only ever get 200 miles on a tank maybe 230 not that bad i dont think

 

[claytucc3]

The computer mileage is usually 25% off. I have tested mine about 10 times and it was NEVER correct. It is a cool feature but not that accurate. Make sure you test manually with fill ups and miles driven.

 

[jlisle01]

The oil was changed about 500 miles ago so it can't be that. It was getting bad mileage before and after the oil change. For those of you who have tuned your car what do you recommend that I use, the DiabloSport Predator or SCT Xcalibrator? Those are the ones I'm looking at getting. Will one work better with my MMR intake? I'm looking to get some better mileage from the tuner. Are they pretty easy to use in your own garage or do they require a shop to figure out the tuning?

I'd find a dyno shop in your area and buy whichever tuner they have the software to use. I bought my X-cal first and then found out that the nearest SCT tuner with a dyno is 180 miles away. Find the shop first and then get the tuner.

 

[Blak05GT]

Alright, problem solved. The tune is definitely off. Car is running lean right now. I went to a Mustang shop in my area and it's going to be dyno tuned next week. Can't wait! Thanks for everyone's input. 15 mpg or less was starting to get on my nerves! I'm getting 278 at the wheels right now, hopefully I'll be somewhere in the 290-295 range after the tune.

 

[claytucc3]

Good stuff......good luck

 

[Blak05GT]

Well, the tune worked out well. I've only driven the car for less than a day but I'm getting better gas mileage already and the car maxed out at 301 RWHP/312 RWTQ. Not bad. It really kicks you back in the seat now! Thanks for everyone's comments on this thread!