very poor mileage @ 11mpg
 

2003 E53 3.0i petrol automatic (UK)
I have never had a vehicle with such "poor miles per gallon"
I am not heavy footed by any means but averaging 11mpg urban is total crap!
I had a 2002 Shogun Sport 3.0i auto that only had 4 forward gears and got nearly twice the mpg @ 20mpg (both the shogun and X5 are roughly same size and weight)
Is there anyone else that had poor mileage per gallon and found the reason why :dunno:

Youve definitely got something wrong there . Mine is a 3.0i ,55plate, I do drive it quite hard in and around town , Consett in Co.Durham so lots of big hills to.Average about 15 around town and 16.5 ,funnily enough with the caravan on the back, on a longer journey.
I have heard that a new set of plugs and leads tend to make a difference though.

Wow...that's got to be 30-40% below expected assuming you're talking UK gallons. I'm surprised you haven't set a code with mileage that bad! How many miles on her and how many since the last major inspection?

I'm always complaining about my poor city mileage on my 2005 4.4 (although I'm always flogging it hard around town) and I'm getting the equivalent of 17-18 UK MPG.

2001 4.4 city 9 -> 12 mpg and freeway : 16--> 19 ( heavy foot)

I`ve only had the X5 10 weeks 64k on the clock and yes UK gallons @ roughly £6.00 per gallon! need a petrol tanker running behind me at this rate.
Checked HT leads and plugs which give very good sparks, no leads shorting/bridging.
Also have the dreaded parasitic battery drain, got to charge battery every day or two, renewed battery, renewed fsu and disconnected retro bluetooth, tbh this is the worse car I have ever had for faults! BMW have in my opinion went downhill for reliability, this is my 3rd Beamer and my last:(

Pull your spark plugs and see what they look like.
When was the last time you changed your fuel filter?

I suggest pulling the DISA valve and seeing if there is a bunch of oily residue in the intake.

If you are getting horrible mileage and no engine faults, that means something is increasing the air/fuel ratio and the computer is adding fuel to compensate.

There is either too much air, not enough fuel, something foreign (CCV blowby), or all of that going on in the chambers.

I wouldn't expect your oxygen sensors to have gone bad, but you could replace those and see what happens if you don't find cheaper, more obvious problem.

Thanks Lo Jack,
very informative! I will take a look at what you say! if beyond my scope I will get my mate (mechanic but haven't seen much of him lately) to look at the things you said!

Thanks again;)

Did the DISA, replacing/cleaning the MAF solve your issue?

Do you drive a lot uphill ? My 4.4 does 13 in city with a lot of stop and go but when i drive uphill i get 9 mpg