Is anyone having problems with their 3 hatch's gas mileage? I've had my 3 almost 3 months now and the city mileage has been horrible. I've been getting between 15 and 20...and it should be getting around 25. The highway mileage has been fine, on 2 long trips I got about 30 or 31. Is this something I should worry about or will it just take time for it to open up?

 

Heh. Just drained the first tank in my new 3s and only got 22 mpg. But I've been driving like a lead-footed teenager burning daddy's gas. I anticipate getting 25+ in city, but that's with a manual.

 

mikeg, you need not tell us how you are driving. If you are getting 30 on the highway but 15 on the city, then you probably have a led foot. On the highway you get to a certain velocity and then you turn on your cruise control. No more lead foot there. In the city you are constantly stoping and accelerating, and by how much I bet you might be close to flooring it a lot when you accelerate. If you are doing that then that is your problem and you need to slow down a bit. Still, 15-20 is pretty bad. Either you like to redline or there is something wrong with your car.
thats my two cents.

 

Also note: DON'T BEAT ON YOUR CAR IN THE FIRST 1000-1500 MILES. The break in period has a huge impact on your vehicle's 1)Long Term Gas Mileage 2) Reliability 3) Dyno Curve and HP

I know getting a new car with a decent amount of horsies is tempting, but you ahve to be careful not to rag on the car, keep it at constant speeds for extended periods, stress the brakes, axles, transmission, etc, and just be nice to her for the first 1000mi or so. Gas mileage will get better after the break in period, but don't kill such a beautiful machine.

 

i have the same problem as mikeg, lousy mileage (20 mpg city, 23 mpg highway) compared to advertised economy. seems everyone is saying different things: need break in vs. no break in; cruise control vs. varying speed on freeway. does anyone actually know as opposed to voicing pet theories? i've had my 3 for about three months also, don't drive it much aside from commuting to school (2 miles, daily) or parents' home (550 miles, monthly), total mileage now is about 1700. what's the dealio?

 

That's the thing though, I DON'T drive the car hard at all while city driving...or I wouldn't even bother asking about the mileage. And what do you consider driving the car hard anyway? I don't accelerate quick, don't shift late, don't downshift to pass, etc. I know all of this eats up more gas. That's why I'm worried, it doesn't seem to make any sense to me. I've even tried to take it EXTRA easy on the car the last 2 tanks and the mileage seems worse. I'm a little more than halfway through a tank of gas now and I've only driven 110 miles...that's like 15 mpg! I'm taking it to the dealer on Monday so we'll see what they have to say.

 

according to the manual it says to NOT drive it at constant speeds for long periods and that the break in period is only like 300 miles or something low like that.

 

He said not to drive it at constant speeds. and the break in period is more than 300 miles

 

If you are fortunate enough to own a 3, go to the car, pull out the owners manual, and look up the breaking in instructions....yes, it's in the manual. It's usually between 600 and 1200 miles for the break in period. Now, this period is not the entire break in period of the car, it's merely the time it takes for all of the internal engine coatings and machined edges a chance to wear off and oil has been able to make it to all necessary parts of the motor for optimal perforamnce. If you run the car hard before this all takes place, you can mildly damage the motor, inlcuding minor stress lines and wear lines (scratches essentially) on the parts riding against the new machined edges. When you run the car harder (actually I think defined in the manual...don't exceed XXXXRPM...like 3.5-4k), it puts more stress on the parts, and more pressure against the parts of the engine that may not have reached optimal lubrication yet. When driving at constant speeds, you're putting wear on the same locations in the engine, so you'll end up with parts more worn than others, giving flat spots in your motor.

Beyond this 600-1200 miles, there are still parts that will "loosen up" over time, thus you probably won't get optimal gas mileage until like 5-10k miles on the vehicle. As for your specific problem, if you're only making a 2 mile drive to work, and your engine doesn't have a chance to get warm, you're probably running a little richer than normal, which would decrease your mileage eve more. I'd say give it till about 3-5k miles, and see if your mileage has increased. It likely will, and will continue until your engine is completely broken in. I've broken in two pr5's in the last two years, both of them started out at about 22/27. The first vehicle ended up about 25/31 and the newest one is about 26/34 at 10k....so just give it a little time.

Again though, to those others with new 3's....read the break in instructions in the manual and follow them....it will make your reliability better, hp higher, and your gas mileage better.

 

With my Mazda3i 4 door, 5 spd manual, I got 35 mpg on the first tank and 37 mpg on the second tank. The first was day 1, no speeds over 60, varying speed and engine rpms between 2-3 k RPM (cruising), the second tank was on day 2 of owning the car, I varied from 2-3.5k RPM (cruising) and speeds up to 70 mph. All highway miles. I haven't done any driving in just town yet.

As for town miles. How many miles do you drive to work each day and at what speeds? If you drive 1 or 2 miles to work/school each day, and never more than about 3-4 minutes at a time, as someone else was saying, your vehicle will always run very rich as it never gets warmed up. I would expect 15-20 mpg, or worse, especially with an automatic (I think Consumer Reports got around 20 in town with their automatic, I would have to double check). And that is with the 4 door. I think they got 20-40 (avg. of 30) with the auto, and 24-42 (avg. 33) with the manual. I imagine the hatch would be worse, say it were 10% worse, that would be about 18-36 with the auto and 22-38 with the manual (just made up numbers for example).

Just to add, if you do only short trip town driving, make sure to take it out one the highway once a week or so to burn out any carbon build up in the engine/exhaust system from running rich. This will keep your car running better.

Also, in winter months, short trips are really bad for gas mileage, I have had several four cylinder cars get less than 15 mpg (i.e. 10-14 mpg) because of short 1 mile trips with a 1 minute warmup at each end. Think of those people in the trucks that usually get that mileage at best. One of my friends once got 2 mpg in his 440 ci ford pickup, that usually got 10 mpg on the highway, in similar driving conditions.

 

Personally I belive this guy:

http://www.mototuneusa.com/break_in_secrets.htm

Run the hell out of your engine to break it in, and change the oil in the first 20 miles.

-Dax

 

For what it's worth, my first tank, almost all city, got me 20. M3, 4dor GT standard.

 

I'm involved in dirt and asphalt short track racing and over the years I've spoken to many very reputable motor builders and there are many, many theories on breaking in an engine. I don't what to believe. My car just topped 1,200 miles and I filled it up and I'm getting 25.8 miles per gallon. With that said, the bulk of my drive is backroads with a good number of stops and up and down speeds due to slowpokes in front of me. I drive the NJ Turnpike for about 9 miles and then more city-esque style driving on route 18 for about 3 or 4 miles I would imagine. I'm thinking that the gas mileage will definitely go up but I can expect anything fantastic with this car based on the type of driving I do, lots of stop and go's and such. And just for the record, this tank of gas was relatively mild and while I got on the gas pedal a few times, no redlines or anything crazy, that's for sure.

There's my gas story. Sure is nice to see gas prices at some stations getting ready to top $2 a gallon for regular. NOT!

Be Good, JP

 

I've actually noticed an improvement in my Gas mileage with my 3 (2.3 litre engine). Most of my driving is highway, but I've done 510kms so far, and I still have gas left. Last time I filled up when the light came on and I had done 500kms. When I first got the car in the fall, i was doing between 440 and 465kms per tank. So maybe there's something to the theories of "breaking a car in".

 

I've been pretty disappointed with my gas mileage so far, but I'll give it a bit longer before I'm concerned. Have about 1400 miles on my 3 hatch. Only getting 22-23 (max) mileage with half city/half highway driving. My morning commute is all highway. My afternoon commute is around town. Since it's been cold, there's been some engine idling time that is probably reducing my gas mileage. The next month should tell a lot. Not driving like a grandma, but not like a kid who just got my license either.