PeachParts Mercedes-Benz Forum - View Single Post - Terrible gas mileage: 17 mpg mixed driving

LUVMBDiesels · #19 08-13-2008, 07:45 AM

Quote:

Originally Posted by t walgamuth

Tires can vary a lot in actual size even if nominally the same size. A taller tire will compute to lower economy but actually be better on consumption. The only way to be sure is to measure the actual diamater of before and after.

Or you could check against the mile markers on the interstate.

Tom W

The tread can also affect fuel economy. When I put more agressive tires on the Suburban -- same size as stock, my mileage went down by 4mpg.

It has taken a lot of tweaking to get it back up to 16mpg combined.

I would also try this to look for fuel leaks. Get some clean cardboard and put the car on top of it. Start and run the car while shining a bright light underneath. You might have a leak that is only happening when the system is under pressure.

I would also run the car and really examine all the fuel lines under the hood.
I had such a leak in the BMW. I got crappy gas mileage until I found and corrected it.

Does this car have a cold engine enrichment booster? If so, it could be stuck open. That was another issue with the BMW that cost me mpg... Check all the temperature senders to make sure they are connected and working.