likenew94stang

My 2000 GT 5spd has been getting TERRIBLE gas mileage. It has an O/R X Pipe, Bassani Catback, and a K&N intake. It has 88k miles and I recently changed ALL fluids (trans, diff, etc), and plugs. I do not have a set of MIL eliminators yet, but I will be getting them soon.

I've been getting around 7-8 mpg in the city. I dont drive the car hard AT ALL! I really dont. Its NEVER raced, it's never driven hard ever! I can't figure out why my mileage is so low. I go through half a tank (on the gauge) in 45 miles. I bought 5.3 gallons last time and that ran me for the 45 miles.

Anyways, my question is will a dyno tune fix this problem? I know I dont own a mustang GT for gas mileage, but damn...7-8 is kind of ridiculous. To me, it's worth the $250 tune.

Will putting cats back on the car make any fuel mileage difference? What about when I put the MIL Elim on it?

Sorry for all the questions, but this has been driving me crazy!

GolfmanSpeck

As far as I know, you should get better gas mileage without the cats. Also, I believe the rear o2 sensors are only used to measure a difference between the o2s in the front so that the computer know that the cats are working. As far as I know, the rear o2s don't do anything to modify the a/f ratios. Some one correct me if i am wrong!

roush17

Wow, I can't believe that sh*tty mileage! I would have it looked at before tuning it, but who knows, they might be able to fix it. I would call the tuner and ask about your situation if it was me.

likenew94stang

Its not throwing any codes, Ive checked several times. I have no problem having someone look at it, but I just cant imagine what would be causing it other than poor a/f tuning.

korn253

You must be running extremly rich or something, the worst gast mileage I get is 15 mpg and thats getting on it too, and I have pretty much the same mods with 70k on the clock.

Dan04COBRA

You don't have a CEL on for the mid-pipe yet?

Some people experience little to no difference & others see a drastic change in gas mileage. I would check for any leaks in your exhaust & get those eliminators ASAP.

PaintballFreak

I'm sure you thought of this but just in case, how much gas do you get in the tank each time you fill her up from empty? about 13-14 gallons?

PWORLDSTANG

Since there is no telling what is causing you to eat up so much gas, a tune may or may not help. But it sounds like your car is running way to rich for whatever reason, so a tune should help.

likenew94stang

When I measure mpg I always start from COMPLETELY full, drive the car for 100 miles or so then fill it COMPLETELY back up, then calculate mileage. It's a really accurate way of doing it.

And yes, I am getting a CEL for the rear o2's because of the Xpipe. I am just not getting any other codes.

Do you all really think that the MIL elim's are going to make a difference in gas mileage????

Brute03

if it's any help, i drove my car for six months without mils, and after i put them on it didn't make a difference in economy.