I have a MCS 08 and now have reached 58,000 + miles and the last 2 tanks,I've noticed a decrease in fuel mileage from 38 and 39 down to 36. Should I be concerned?

 

You're lucky you're getting that - I'm only getting 29-31 with mixed highway and city driving.

 

That seems really high! I wouldn't worry about a couple miles per gallon, but I would worry if it started getting towards the low 30s if you're used to getting around 39.

 

I wouldn't be concerned, I'd be thrilled to get 36 miles per gallon.
Go to www.fuelly.com and lookup Mini '08 MCS. I log all my fillups there and my average mpg is 31.5 and that's with 16 fillups.
I sorted the list and there are nine 2008 MCS Mini Coupe owners including myself who are logging their fillups. The best is 32.6 mpg and the worst is 27.7 mpg. The list includes manual and automatic transmissions as the site doesn't ask transmission type in the profile.
My question is, How are you getting 36 mpg? Are you going by the car's computer or are they actual miles recorded by the trip odometer?
If you are using the trip odometer and those are actual numbers, please post your secret!

 

I get about 30-32 mpg, but then I can't resist romping on the gas pedal a lot!

Dave

 

I use the trip odometer then divide the gallons I put in.Car's computer isn't correct,it shows I would be getting 41.1 MPG..
My daily drive is 80% FWY 100 miles round trip.According to CPU my avg speed is 46.9.

 

Congrats on the mileage, I only get 30-31 but keep my foot in it all the time, one of these I'm going to drive reasonably for a tankfull and see what I get.

 

The most immediate thoughts that come to my mind would be something with the tires to cause such a drop in mpg. If those are ok, are you due for an oil change and maybe getting a bit low? Check air filters and such? Any possible external factors (changing temps, gas formulation changes)?

 

How about this...

It's approaching winter, and the gasoline blend has changed. You will get worse milage in the winter, due to the lower Reed Vapor pressure of the gas.

 

Your commute is ideal for best mileage and your calculations should be accurate. I would look at the above suggestions and come to think of it, I should check the air pressure in my tires today. I try to check them monthly, a habit I got into when I had the run-flats. Air pressure definitely makes a difference.
The only other thing I can think of is I believe Mini suggests replacing the spark plugs at 60k miles. Could that be a solution?

 

That's funny. I usually only get about 21 to 22 MPG in my auto Clubman S in Sport Mode full time, unless I'm driving on the freeways all the time, then I can get 30+. I recently did Way Motor Works Diverter Valve/BOV, and have been able to stay in non Sport mode and still have fun..the valve makes better use of the turbo. My most recent tank I got 360 miles to my tank where usually I'm about 220-250 with a very heavy foot in mostly stop and go traffic. And with that 360, I still had romped on the gas a few times, so I probably could squeeze out 400 miles in my city traffic.

My point is that MPG is very much determined by driving style.

 

I got 60K+ on my car and I'm still getting 32-34 in the city with mine and upwards of 38-40 on the highway. It all depends on how I'm driving and what the weather is.

I filled up today and my last tank I got 32mpg with all city driving, although it's been pretty cold in the morning.