New BMW owner. A 2004 530i. So far... 60 days... I'm extremely happy. It is the ULTIMATE DRIVING MACHINE!

So far I'm getting 20 to 21 miles a gallon all commuting to work and back. Mostly stop and go but with a few stretches at 55 mph. OBC says my average speed is only 27 mph tho.

Here's the problem... my OBC says that I'm getting 24 to 26 miles per gallon. Anyone else find a difference in when they manually calculate miles driven by gallons filled up?

Should I have my computer checked or can it be adjusted?

The tires are stock so I know its not the wrong size or anything.

 

Go into the idrive settings and make sure it's set to US gallons, not UK gallons.

 

there is a way to adjust it. its in a hidden menu. Details of how to find it are on this site.

 

My actual mileage is 1.5 to 2 mpg LESS than the OBC says.

 

Fill your tank full, Push the odometer trip to zero
Next time fill your tank to full (say 10-Gallons/Liters ), Note the miles driven (Say 300 miles)
Divide the 300-miles driven by Fuel (Liters/ Gallons) i.e., 300/10= 30 miles per gallon/Liter
This will give your average MPG/MPL = 30