Lucky people/// i get 13 MPG 95% Streets 5% HW .. I stil ldont get what im doing wrong that the gas is used up soo fast.. i fill up every week

You aren't doing anything wrong... You do a lot of city driving, which is really really bad for gas mileage. How hard (if hard at all) do you stomp on the gas pedal to get to the next stop sign/light? Are you carrying a lot of extra weight in your car?

Got 26 mpg with my "old" '04 3.0 which had ~15k miles, and am now getting 21-22 mpg on my '06 3.0 which has ~2k miles. I'm optimistic that it'll improve....

i do stomp on it hard becasue the x3 reallyd oesnt have such good acceleration unless you step on it. Especially form going from a G35 to an X3 theres a difference. I like driving fast but the car just doesnt hack it...

One thing i've tried to do to improve my city mileage is learn the stoplight timing on regular routes. Romping on it to the next light, stopping and starting again kills it. I actually get a kick out of seeing other people that whiz by me sitting or just starting up again at a light as I casually pass by them whithout even hitting the brakes. (Saves on the brakes and wheel cleaning too!) You get there just as fast but without all the waste.

89 octane? My `06 3.0 requires 91. Why are you using 89?

DrT: There have been a litany of threads on "what gas to use/what brand/what octane", etc.

If you like 91, use it!

For some background reading and the continuing debate on gas, use Search.
BR,md

How about three litre diesels?

I have -04 3.0D and I drive 95% city, 5% highway, it takes 11 litres per 100km (21 mpg).

My current car is a Subaru Outback 3l and I expect in ~ one month the X3 3.0d.
Subaru eats 23l/100 Km and I hate this !

This discution is for Petrol or Diesel engines ?
Mane if my X3 will eat only 11-15% in the City (Buchatest-Romania) I'll be the happiest ppl on earth.

It wont take over 13L/100km in the city, thats for sure. Eaven if you sit on the gas pedal it wont.