I have had my 2006 MC since late October 07. I absolutely love it! I ended up having to take it to the dealer to have an oxygen sensor replaced. Since then, I have noticed my mileage going down. I only drive on streets in LA (I know insane) and my commute is 13 miles each way which can take anywhere from 30 minutes to hours..... When I first got the car the computer had it at 23 miles to the gallon and it's now down to 18.8!!! Not complaining as my last car a Jeep was getting 9 miles to the gallon. Could it be the oxygen sensor or the fact that I have just started to use the AC as it's summer (didn't start using it until about May which coincides with the sensor) Or should I just take it into the dealer? I have another 6700 miles til she needs service. I've only just put 4000 miles on the car over the last 8 months (just about to hit 21K)

Also does anyone have any suggestions of the best way to cover a burn on the driver's seat?? Yes I cried when it happened but it was either burn the seat with a ciggie or get into a horrible accident. It's on the red fabric type seat.

Thanks

Cat
http://tvholicsanonymous.blogspot.com

 

18-23 mile a gallon!!?? my 2007 MCS gets 30+ and thats on city streets driven spirited with a cold air intake. something is wrong with either your computer or engine. and yes i know yours is a tritec and mine is a prince engine, but still.

 

Consider yourself lucky. My doctor gets 28 around town in her 07 MCS while driving like the old lady that she is.

 

Crap, I'm getting the same code for the O2 sensor and was hoping I wouldn't have to replace it :(
To answer your question, it does sound like it may be from the AC and maybe some changes in how you drive. I've seen about a 2mpg drop on average this summer although I'm doing better recently but I think that may be because I'm doing more highway driving, and keeping the speed-down from that.

 

I noticed that too. I've gone from my normal around town of 25 - 27 down to 23 - 25 with the AC on.

One thing is for sure ...its tough to motor in spirited fashion with the AC on.

 

agree,.......A/C will kill your mileage, and w/ a Cooper, make a noticeable difference in power.

Steve

 

Looks like it's going to be 360 miles out of my last full tank fill-up. That includes a bit of A/C usage and at least 2 spirited drives.

I feel like changing my spark plugs now just to see if I can get it bumped to 400.

 

I have an '05 MCSm with a 15% pulley and a DDM Works CAI. My gas mileage is terrible. It had been about 20-21 in town, which is strictly going from one stop light to the next, mileage that I was not very happy with. The hwy mileage occasionally would get to 30, but not often. Since I had the pulley put on my city mileage has dropped to 18-19 and my hwy is no better than 27mpg. Someone told my O2 sensor could be messed up but the car runs great and no check engine light has come on. Any ideas out there?

 

I have an '05 MCS. I'm getting an average of 25.5 miles per gallon.. and I consider my driving a bit conservative (most of the time). I don't know how some MCS's get 27+

 

I have a 04 MCS with a 15% ,CAI and Air Diverter,with a M7 Scoupe, Very rare that i even see 25 on the highway unless I am driving 60 MPH, no complaints.

 

A bad O₂ sensor usually has more symptoms than just poor fuel economy.


If you had to replace it...

Real OEM says the O₂ sensor runs about $270. The car has two, pre-cat and post-cat. Pelican parts has the sensor for $220 each.

 

I'm getting 29mpg combined city and highway but mostly highways. It has bola exhaust and CAI.

 

I get 20 with the current power i have now.
I spend 425 a month in gas though. :*(

 

Considering your mods I would guess tires are also a big expense. Or they would be for me with that much power.

 

We are getting around 24 mpg. This seems to be acceptable for the way we drive, and the equipment and mods.

 

We are averaging 25 MPG city in our MCS with the mods listed in my sig below. It's at the dealer today getting a new 02 sensor installed. Will keep an eye on MPG and see if anything changes for the better or worse.

 

Those averages.... are they manually calculated or number from your OBC?

My '06 MCSc averages between 26 - 27.4mpg (manually calculated) for mixed driving of 40/60 hwy/city. The OBC says my average speed has been around 27-28mph. For the current tank, I'm aiming for 28-29mpg by gentle acceleration and shifting at ~2500 rpm. Fun factor's real low driving like this. My tire pressures are on the comfy side 33F/28R.

 

If you are getting 18 mpg. I would get her into the dealer well before your scheduled maintenance. I have an 06 cooper got it May 07 On the open road I have gotten up to 40 mpg, in the city with ac going full for the summer months I get from 30 to 33 mpg. there is something wrong in your system I would let MINI take a look and you certainly should be getting better milage than 18 mpg.
Happy Motoring

 

I get 28-29 on average with about 95% of those miles being highway miles. My computer tells me I get 32-34 but when I calculate it by hand I see that it is very wrong.......Mine is a 03 MCS

 

With the OBC I was averaging 24-25 mixed driving before 02 sensor was changed. I was very pleased to discover after it was changed I was averaging 27.5...then I realized they reflashed my software and wiped out the Dinan software. Once I had the software re-installed it went back down to 24-25. More power with the Dinan but it obviously sucks more gas. Apparently though the 02 sensor didn't make much difference in mileage.

 

Makes perfect sense, the Dinan software is asking for more out of your motor. Where as the 'stock' flash is more suited for everyday driving.

 

rediculous the mileage we get out of the supercharged s's. That would be the only reason i would ever even contemplate going to the turbod mini. Even though i did get the mini in part becuz i was expecting good mileage, but now i guess i hav grown to love it enough that it doesnt matter. I was gonna get a v8 s4 tho, and im sure id love that to.

 

i get obc average of 26mpg, 50/50 hwy/cty. i did notice going to a colder plug helped and took the tire pressures to 34psi. however i notice the biggest difference between using unleaded versus premium the premium gains me a solid 5-8 mpg better with my driving style. (shifting around 4k) driving 72 on the highway.

 

Considering that the superchargers take power in order to make power, it makes sense it would not get the greatest gas mileage, but for a supercharged vehicle...it's still pretty darn good IMO