Help!! Very poor mpg (7)

X5V8RULES · #1 11-26-2011, 01:31 PM

Im getting a very bad gas mileage ( 7>>>10) in the city ( short trip and some hilly road)i did recently a tune up but it didnt increase my mpg. I i have got an exhaust leak ( according to a loud but beautiful exhaust sound ) no cel. It s 4.4 2001. I drove slowly last night after resetting the onboard computer and i got only 10 mpg. On the highway im getting 15>>18.6 mpg. The x runs like a beast and there is no lack of power .

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motordavid · #2 11-26-2011, 02:17 PM

Seems like a refrain post from the same OP; my orig question remains: have you run a few tanks full and done the arithmetic to see what your 'normal' tank mpg is?

Resetting the mpg readout constantly is like watching the minute by minute stock market on a crazy day, imo.

Not saying there is nothing amiss, but what does several tanks worth return to you in mpg, in your 'normal' driving conditions?

The rest of diagnosing your 'low mpg' is guess work from afar, imo.
GL, mD

X5V8RULES · #3 11-26-2011, 03:35 PM

Is the onboard computer accurate? No i havent done the Arithmetic. in normal conditions i used to get 16 mpg in the city

X5V8RULES · #4 11-26-2011, 03:39 PM

Is it related to the exhaust leak. ?A friend told me that the o2 sensors think that the x is running lean ( air getting in the exhaust system) and add more fuel and kill my mpg .

mattkins99 · #5 11-26-2011, 03:51 PM

Is the car throwing any codes?

X5V8RULES · #6 11-26-2011, 03:56 PM

No codes .

mattkins99 · #7 11-26-2011, 04:27 PM

how did you friend tell you the O2 sensors were detecting a lean condition then? Was he just speculating? Sorry, I took your comment to mean he'd pulled a code that said this.

motordavid · #8 11-26-2011, 05:07 PM

What is different in your opinion, about your car's condition, than the last time you wondered about your low mpg?

Anything learned from that thread? Anything done differently to your car? Still haven't run a few tanks and done the arithmetic?
Still driving with heavy foot in stop and go traffic for the most part? ...

http://www.xoutpost.com/bmw-sav-foru...r-mileage.html

X5V8RULES · #9 11-26-2011, 07:13 PM

I drive my x slower than before. I am resetting my onboard computer every morning (lol) . And i have got now an exhaust leak ! when i wrote my previous post i was getting 12 13 mpg and now 7 mpg. It is getting worse and worse. Soo i need a little clue in order to solve the mpg mystery !!

X5V8RULES · #10 11-26-2011, 07:18 PM

To be clear , my question is the exhaust leak can cause a drop in mpg?

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