So I have an almost stock 03 MCS, with 110,000 miles, that I picked up several months ago, and checking the on board computer tells me I'm only getting ~21 mpg. This doesn't sound right as I keep seeing posts from you guys claiming 25+ .

I've already Sea Foamed my car and have seen about a 1mpg increase, but maybe the spark plugs are just old and not functioning as well as they could be?
what do you guys think?

Oh and my driving consists evenly of stop-and-go and freeway driving.

Thanks!

 

Don't forget to reset gauge. Just press & hold. I was getting 15mph before I figured it out. Now its about 26-30 mph. If that's not the case, it might be time for that stageII maintenance.

 

I'm getting around 23, but that's with all local, short, city trips.

That's significantly worse than my SUV.

 

I topped off last night and according to my computation, I got 28.2 mpg.

Not bad! I used to get 13mpg from my gas guzzling SUV.

 

ya i've already reset my gauge and nothing, what do you mean by stage 2 maintenance?

 

What octane are you using for the gas you buy?
Getting lower octane fuel will make the ecu run the car significantly richer, reducing economy. Same for ethonol content..the more in the fuel, the less Btu's, so the more fuel must be pumped to drive the car per mile.
With my mods, when I drive my car gently, I can get 30.5 Mpg for almost pure highest driving, at about 72 Mph.
I tend to ge closer to 28.5 when i drive all highway...simply more fun!!
"mixed" driving tends to be 25-26 mpg, lower for mostly in town.
Check you airfilter, and seemingly minor things, like choices in tire brands, rim weight, and tire width can drop mpg by a few % each...it adds up.
Try driving a tank of gas imingining that you have an egg under your foot...gentle acceleration....you mpg will go up by a lot, but I think you will find it less fun...some it is all about compromises!!
Do you have any mods on your car? Some can cause pretty dramatic changes in power, and as a result in mpg....
But properly tuned, you will only loose mpg's from many power mods when you actually use the extra power...in my experance anyway!!

 

PS...since your signature says you drive it like you stole it, 25 mpg on 91 octane is not too bad...93 helps lots, especially if you have a pulley, or have been "tuned".
The fact you are running wheel spacers gives a clue to the mpg..are the rims the wrong offset? If so, no big change, but if you changed the size, IE, the outer diameter of the tire, now you speedo, miles traveled on the odometer, and your gearing is all inaccurate....so getting a true mpg is very hard.
And having re-read the op, since you appear to do lots of stop-and-go driving, the mpg is pretty good!!

 

PS if you have a pulley, the plugs IMO should be changed just as often as a JCW...every inspection, so it works out to about every 30k. And always insert them cold, and use a tourqe wrench, and recheck the tightness after a few days.

 

I run the hightest octane fuel I can find, usually around 91 octane and the only performance mod right now is an alta silicone inlet hose that I installed, I'm also running on fairly worn run flat tires. My driving is fairly spirited but I still feel I should be getting better
than 21 mpg.
I checked my stock air filter and it's pretty dirty, but
I'm getting an alta cai soon so that should be changed out soon enough.
soon

 

The inlet hose is mostly for looks, but is nice...keep an eye on the lower edge of it (not where it connects to the airbox), they have a tendency to slip off the connection if not trimmed properly...this let's in dirty unfiltered air..so just glance at it a time or two...
I bet if you went on a level drive with minimal traffic, the mpg would go up to the upper 20's...stop and go is tuff on mpg, especially when you have decent power, and are tempted to use it! If you let it roll mostly in traffic, like a truck, and stay off the brakes, keeping the rpm's low, you might get a few extra....plugs may/maynot be overdue....depending on the cars previous mantance history....
The o2 sensor could be getting "lazy", but still be good enough to not set a light...but it is kinda $$ to swap it out unless you know it is bad...the o2 sensor has no effect fuel use WOT, but when cruising, or gently accelerating, the engine does use it's info to lean the motor....
Mini's do run a bit rich stock, as do all turbo/SC motors, and the bit of black around the tailpipe is common, and ok unless excessive.

 

"I'm also running on fairly worn run flat tires."

 

ya my tires are the stock 17" size, and while I do have 16mm spacers, I don't see how that would affect how my MINI reads how many mpg it gets.
My front tires have about 50% tread left and my rears are at around 10% so they definitely need to be replaced with non run flats soon.

So going out driving right now and taking ZippyNH's advice, I was able to pull out 24mpg highway and steady city driving. Still seems kinda low if you ask me though.

Well thanks guys for your feedback, I'll definitely change out my spark plugs and tires and perform some other maintenance on my MINI. We'll see where I get from there!
Thanks again!

 

We average about 25mpg, mixed city and highway. The Mrs. drives it like a lady would, I tend to drive a little more spirited. 24mpg is not far off.

 

When you say your driving is "fairly spirited"... what does that mean?

At what RPM do you normally shift?

It's not difficult for MPG to drop down to the low 20s.

I've been tracking fuel consumption for my '06 MCSc. Using manual calculation, get about 26.4 MPG (50/50 hwy/city) by keeping my shift point around 3000 RPM. For fun driving, shift points in the range of 3500-4500 RPM, my MPG will go down to the low 20s.

This is for a stock motor, using California 91 octane (castrated) fuel.

 

MiniR53, it sounds like (like me) you need an alignment. with tires being old i am assuming the car has not been aligned recently. a spot on alignment can make all the difference when talking about mpgs. you can lose as much as 3-4 mpgs just from a bad alignment! I have fallen to the range you have with my car as well. I know it is because of the alignment on my car due to the need for a new tie rod and work I have recently done on the suspension. get it aligned at a trusted shop and that should help a lot

 

Ya my car could be due for an alignment soon, I'll have that done soon (after I get new rubbers, of course!) and see how that works out, Thanks for the tip Ksminiman

@ Cadenza & Muzak, The sad thing is I was getting 24 mpg while driving carefully, keeping the rpm's as low as possible (around 2k) and with my usual driving, I'm shifting around 3k to 4k on city streets (not stop-and-go) and around 4k to 5k on the highway.

 

edit for last post: (my phone won't let me use the edit button above, only post)
but I took another look at my rpm gauge cause what I said earlier looked a little high. On the highway I'm revving an average of 3500 and on city streets I'm shifting around 2500...I will occasionally redline on the highway though

 

Hahaha. 20mpg? My V8 seven series (which I drive the snot out of) gets about that avg on the OBC

 

I drive pretty aggressively at times and still average 28-30 mpg mixed driving. Check your plugs and air filter.

 

i get about 25mpg 93 octane sometiems as low as 18 in the city. my '90 caddy gets better MPGS

 

It helps a bit to keep your tire's pressure at about 36-38 lbs.

 

34 front 33 backs are what I keep mine at. I can get 8 - 36mpg, depending on how I feel and what road =)

 

I drive all around and no significant highway driving but i get a honest 34MPG on my stock '05 Cabrio, running 93 Octane. Hard to find 91 in these parts. I do go to 5th gear whenever I can. My Cool Blue Metallic baby only has 54k on it. I am the 2nd owner.

 

I drive a little over 100 miles round trip on the highway and average 27+ mpg at 80-90 mph on the way to work with stop and go on the way home. 95k on the ticker.

 

MC or MCS and what year? makes a big difference. driving style? please