Hello,

I have 535i which I bought in March. I commute ~50 miles a day so I am aware of mpg I get as it was one of the reasons why I did not get 550i. When I bought the car I was averaging ~23.5 mpg (mostly highway), however, lately it has been droping dramaticaly - 19mpg. I do not think that I push the car harder as with last tank I tried to be as smooth as possible.

Can this drop be because of the hot weather we have here in Chicago or it is some mechanical issue? I don't remember that my 330Ci would get a drop in mpg in summer, however, it was not a turbo engine as well....

 

hot air makes any engine lag. you're probably just giving it more gas to make up for the difference.

 

On a recent trip from Titusville, FL -> Sarasota, FL -> Titusville, FL I averaged 27.5 mpg in my wife's '07 550i. This was over the course of 410 miles. I kept up with traffic ~75-80mph. Auto trans in D-mode (not DS-mode).

We seem to do about 16-17mpg in town. I tend to keep in in DS-mode, which cuts down on the economy significantly.

I plan to take the same trip next week. Last time we'd owned the vehicle for less than 24 hours, so we were still curious what the big peddle on the right would do. Now that we've had the car for a month, I'm VERY interested to see what I can eeeeek the mileage up to when I'm being conservative.

The 550i is a highway EATING MACHINE. It's around town mileage is disappointing, but it seems to average out quite well on the highway. My wife's 550i cost's less at the pump than my Toyota Tacoma costs (17mpg combined.....15mpg city, 18mpg hwy). I only wish my Tacoma was as comfortable as our 550i with 20-way adjustable comfort seats. I even swapped my cloth seats out for Katzkins Leather upholstery in my Taco. It is still WAY inferior to my wife's Bimmer.

 

My 550i strictly puts on only hwy miles as I have another DD. I drive the 550 twice a week on a 60 mile stretch. Car averages 24.3 mpg.

 

I'm only on my second tank on my 545i and its not looking too good...

11.7 MPG by my calculations, the computer says 12.5 MPG

 

my mpg went up by 2 1/2 miles since I started to use "only" Shell gas. Guess there must be something with the "TOP TIER" gas concept after-all.

16.6 MPG, and seems to be getting better with every tank of gas...........