I have a 2003 ML500 with 105k on it now, purchased it used with 60k on it two years ago.

I have been consistently getting 16 mpg around town and 20 mpg on the highway. In the winter, its much worse - 13/17 or so. Mileage depends more on temperature than any other car I've owned.

I replaced my spark plugs at 85k miles or so. Had the dealer do it. I also change the air filter about every 15k miles. Mobil 1 synthetic - 5w-40 I think - I buy it at the dealer for less than $6 per qt.

The key to good fuel mileage on the hwy is to use the cruise control. I've even observed 21 mpg driving at 85 mph across Indiana at night with the cruise control on, AC off, in 60F weather.

Considering I would get maybe 23-25 mpg in the old 617 diesels I've owned, the fuel mileage of this ML500 isn't too hateful at all.

CB