LaicepsYdobon

Now I know why I have so much work to do; the rest of the world is just f-ing around with useless statistics

I used to track my gas mileage too in an app that I developed. Then I started to use Fuelly to do it but now I lost all interest and stopped all together. I feel much better driving around not having to worry to try and break one of my personal records of getting the most milage between fill ups. Now I fell more liberated the deeper I push the gas pedal

Arrie

I have been doing mpg calculations for a long time for one main reason: It most often is the first indication if there is a developing problem with the engine or its control systems.

The way I do this is I fill up and reset trip counter. Next time I fill up and do the simple math and reset again.

For me this is easy because 85-90% of my driving is highway. City driving just don't count as it is so random stop-and-go you cannot really know if car has a problem or not. Only steady speed highway driving tells you on possible problems based on mpg.

Another thing is it tells where the good quality gasoline is and I can tell it is not at some Race Track or similar discounters.

Best ones I have found at Chevron and some BP stations that used to be Amoco. And I don't care if it costs 3.30 vs 3.00 when it is worth the money.

Tjdehya

With 100miles highway 60-70mph and 8miles city (non rush hour), would you say that 20mpg is bad? That’s my new daily commute and I was expecting much closer to EPA estimates even though this is a V8. I got 406miles and the car needed 19.8 to fill up, trip computer says 22.3 from reset. And fwiw every day when I get home the "from start" trip computer says 26+mpg, yesterday it said 27.6. I have pictures of all this but I am too lazy right now.

I guess the trip computer could be lazily calibrated exactly the same for E350 and E550.

Arrie

I think you should get better than 20 mpg on a trip of 108 miles long and 100 miles of it on highway going only 60 - 70 mph. When I drive 70 mph speed my car fuel consumption shows around 28 mpg and with steady speed highway driving it is quite accurate.

One thing that puts the mpg meter off from the real number is that I think it does not measure when car does not move. I'm not absolute sure of this but Audi was like that, i.e. it did not count mpg when car was stopped. This means you can get really good mpg value in the display but bad real value if the car idles a lot.

hanjaya1

Hi Tjdehya, do you realize that the trip computer always give you better gas mileage calculation? Because instead of 22.3 mpg, it should give you 406mi/19.8gal= 20.5 mpg (8.8% of error).

MB needs better sensor accuracy in my mind.

El Cid

My best MPG was last Spring driving 65 on interstate using cruise with the A/C off and windows closed. Sun roof was open. Road had about 40% mild hills and rest flats. TP is 32F/37R, 2 Lbs over lowest recommended.
Got 32 MPG.
BTW, when I am stopped, the MPG indicator goes to 0. Find it interesting that the "instant MPG display" cannot show better than 40. My previous cars used to go to 99 when going down steep hills.

RJC

I think the almost 4000lbs of weight may be the biggest factor, it's a lot of mass to push around especially with 258 lb ft of torque, that's another reason the stop and go mpgs are poor and the highway mpgs are so much better.