I wish I gforgot the trailer...
You did not mention your year and model, but from what I am getting in this thread, the 2005 model seems to be a pig.
I wonder what the actual weight difference is.

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regards,
Sab.
'07 ML320 CDI (398 ft lbs / 1400 RPM)
'02CL 500
'91 928 GT Supercharged

Looks like you have plenty of responses, here's mine: '98 ML320 since new, easily 22+ combined city and highway. I've never measured just one or the other.

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Francis E. Abate
Automotive Restoration & Preservation
Sheet metal, trim and upholstery

Seems like the trend is the newer the ML the worst the gas mileage!
I used to have a '98 and like other people reported, i took my 22/23 mpg for granted when i got my '01!
I was in for a surprise, my '01 with the M6 pkg barely gets 18 mpg!

You are right and that is a poor trend and a sad sign for Mercedes. I will not buy another new ML. If it is better to buy the older model it's a scary sign...

__________________
regards,
Sab.
'07 ML320 CDI (398 ft lbs / 1400 RPM)
'02CL 500
'91 928 GT Supercharged

My 99 to date has not gotten better than 18.7mpg but no worse than 17 for city/hwy driving. I have never driven over 150 miles on the fwy on one tank so i don't know if I would break the 20mpg. For the record, I calculate the mpg by dividing gallons used into miles driven to get the most accurate reading. I will be adding a K&N (drop-in) and my neighbor who owns Tornado said he would give me one to try. I hope to break the 20's for city/hwy driving.