is anyone else getting crappy MPG?

N

nappyjim

Member
I posted this on another M3 board without much success.

I got an 04 and it has 6500 miles on it, manual. Now i got it in the summer and i was averaging 24mpg. Now this is after break in and i RARELY brought the rpms above 4, let alone 3 and still got crappy mileage. Now its cold out and its getting even crappier!! Last tank I average 18.9 MPG! WTF is going on here? (argh)

I have a lot of questions to ask you people who also drive manuals.

1.) When do you shift to 2nd gear? I usually shift at 3k rpms.

2.) If you going 40-45mph do you shift to 5th or stay in 4th? I heard 5th is better cause of lower rpms, but then i heard 4th cause the engine is actually burning fuel more "properly" in 4th, which leads to better mileage.

3) How long do you need to warm up a car when its cold? In the morning I let it sit for 10 min. Any other time during the day I will sit there till my idle drops to around 1k.

4) Is higher octane any better for MPG? Right now I use 87. Ive used mutliple brands so its not the brand thats causing my poor mileage.

5) Any suggestions on how I can get better mileage? I already checked my air pressure in the tires. I can drive like a grandma and still get crappy mileage.
 
I think the biggest reason for the large drop in fuel economy is letting the car warm up for 10 Min, that yeilds exactly 0 MPG. I let my cars warm up for the time it takes me to scrap the windows or if the windows are clear I let the car warm about a minute or so. You really need to just let the oil circulate through the engine. Where I live it gets a little cool, last week the temp averaged about -21 C or -6 F and other then everything being a little stiff when you start out everything is fine, and the car warms up faster while driving.


nappyjim said:
I posted this on another M3 board without much success.

I got an 04 and it has 6500 miles on it, manual. Now i got it in the summer and i was averaging 24mpg. Now this is after break in and i RARELY brought the rpms above 4, let alone 3 and still got crappy mileage. Now its cold out and its getting even crappier!! Last tank I average 18.9 MPG! WTF is going on here? (argh)

I have a lot of questions to ask you people who also drive manuals.

1.) When do you shift to 2nd gear? I usually shift at 3k rpms.

2.) If you going 40-45mph do you shift to 5th or stay in 4th? I heard 5th is better cause of lower rpms, but then i heard 4th cause the engine is actually burning fuel more "properly" in 4th, which leads to better mileage.

3) How long do you need to warm up a car when its cold? In the morning I let it sit for 10 min. Any other time during the day I will sit there till my idle drops to around 1k.

4) Is higher octane any better for MPG? Right now I use 87. Ive used mutliple brands so its not the brand thats causing my poor mileage.

5) Any suggestions on how I can get better mileage? I already checked my air pressure in the tires. I can drive like a grandma and still get crappy mileage.
Click to expand...
 
Golum said:
I think the biggest reason for the large drop in fuel economy is letting the car warm up for 10 Min, that yeilds exactly 0 MPG. I let my cars warm up for the time it takes me to scrap the windows or if the windows are clear I let the car warm about a minute or so. You really need to just let the oil circulate through the engine. Where I live it gets a little cool, last week the temp averaged about -21 C or -6 F and other then everything being a little stiff when you start out everything is fine, and the car warms up faster while driving.
Click to expand...

Ok, ill stop the 10 min warmup. But that doesnt explain the poor economy in the summer months.
 
hmmm.... The best mpg I've had was nearly 34 mpg, but that was going damn near 80 mph with the cruise control on (road trip from Ohio to Atlanta). The worst I've had (which was this winter season) was about 24. The fuel mileage improved slightly after break-in and has so far remained somewhere in the 26-29 mpg range with 40/60 city/highway driving. Do you do a lot of stop-and-go driving? On highway driving, I get at least 26 mpg. If you get 24mpg on the highway, then something is definitely wrong.....
 
dajiggalo said:
hmmm.... The best mpg I've had was nearly 34 mpg, but that was going damn near 80 mph with the cruise control on (road trip from Ohio to Atlanta). The worst I've had (which was this winter season) was about 24. The fuel mileage improved slightly after break-in and has so far remained somewhere in the 26-29 mpg range with 40/60 city/highway driving. Do you do a lot of stop-and-go driving? On highway driving, I get at least 26 mpg. If you get 24mpg on the highway, then something is definitely wrong.....
Click to expand...

Not too much city. I live in a suburb. I go to work at 5am, no one is on the road, so its pretty much smooth sailing at 40-45mph. I dont go out much and for instance, i just filled the tank up and went 90 miles on the highway and im like 5 marks away from half a tank. And i had cruise on.
 
I get pretty decent gas mileage. I use 87 octane also and don't usually shift till 3500 or 4000 rpms and still pull anywhere from 26 to 30 mpg. I also commute every day so I do a lot of highway driving and a little city driving. Did you think about checking the air filter on your car. I've heard that if those get dirty or aren't maintained properly they can rob you of good mileage, but I'm not sure that it would have that kind of effect. Good Luck.
 
I get about 25-27 depending on my driving. i generally shift at about 5 grand. unless i'm in the mood to speed then i shift at the redline. i still get at least 25 mpg. i'm sure i could drive the car nicer but that wouldn't be any fun. i would check that air filter though.
 
I've got a 2000 Protege ES 1.8 auto, we've had it since 2002 and its never gotten over 28 mpg... my wife just got a minvan so now the car is my daily driver and its getting 25-27 hwy, 22-24 hwy with the cruise on.. I'm going ot change the oil and filters and do a tune up this weekend, to see if that works... my cousins wife has a 2002 LS manual and they get 34-38 hwy... I don't get it either...

any suggestion on plugs and wires? and air filter? I was going to to go with a CAI but if that makes worse mileage than maybe I won't... BTW I drive 85 miles a day round trip, for work...

Josh

Sorry, not trying to hijack the thread :)

oh yeah, if I use 87 octane the check engine light comes on and then it gets 20mpg.. if I use 89 the light stays on but the mileage improves... if I use 93, the light goes off... weird huh ???
 
Last edited:
thread jacker!!! (fu)

nah, lol its cool.

To whoever shifts at 5k and still get 25mpg, i hate you!

Im gonna check the air filter. But when I thought about that before, i really didnt think those would be the culprits since the car is new... but who knows.
 
it registers as an 02 malfunction.. don't remember the exact code right now.. but the 02's are fine, just had them checked.
 
I average 27-28 mpg fairly consistently, 70% city and 30% highway. Only thing I would say is keep up on the maintenance - just like everyone else has been saying. The air filter was dirty so I replaced mine when the car had about 12k miles on it.

It's possible a sensor is malfunctioning or something - O2 sensors, EGR valve, etc.
How many miles is on the car?
 
dajiggalo said:
hmmm.... The best mpg I've had was nearly 34 mpg, but that was going damn near 80 mph with the cruise control on (road trip from Ohio to Atlanta). The worst I've had (which was this winter season) was about 24. The fuel mileage improved slightly after break-in and has so far remained somewhere in the 26-29 mpg range with 40/60 city/highway driving. Do you do a lot of stop-and-go driving? On highway driving, I get at least 26 mpg. If you get 24mpg on the highway, then something is definitely wrong.....
Click to expand...

34 MPG!! - I did the same thing, 80 MPH on cruise from Phoenix to just west of Palm Springs, and I only got 29 MPG, I only stopped once..... Do you have a 5 spd? I have an AT. Does that make a difference in hwy driving, gearing, etc. I get 22-23 average daily with 70/30 city/hwy. I have not seen a difference in mileage before or after break-in.

Something doesn't seem right here??? (uhm)
 
When on the highway do you really get better mileage if you stay at like 65 rather than 80?

Cause people always say that, but I dont understand how it could be true. On the highway if im going 60 my rpms are at 3000, now if im going 80 my rpms are around 3500. I understand my rpms are higher which means burning more fuel, but Im also traveling faster. So wouldent the increase in rpms be proportional to the increase in speed?

3000 to 3500 is a 15% increase
65 to 80 is a 19% increase

Sould shouldent my mileaghe actually improve at 80?
 
not necessarily.....it's not as much of a linear relationship as you're trying to make it.
Say....3000 to 3500 rpm is an increase of 15% in rpm, but will likely be a 30% increase in fuel consumption.
Similarly, if you're at 2000 rpm and then redline the car at 6000 rpm, you'd likely be burning 10X the amount of fuel even though you've only increased the rpm by 3X.
 
This might sound weird but a tech at Mazda told me that you're not supposed to calculate milage until after 15K miles, which sounded very odd...

I asked him because I was getting around 25 average in my P5 and thought it was low. Now that I'm close to 20K my gas milage has gone up, although it may be due to other reasons.

The 15K thing sounds like bs, any thoughts?
 
I have 45k on my p5
(just bought it) but I mean the first tank went 320 miles and ya know since I just bought the car there were a few spirited moments and a lot of hwy driving (100mph)

and I got 26 mpg so 320 miles in 12 gallons
I wasn't complaining!
 
Dim said:
The 15K thing sounds like bs, any thoughts?
Click to expand...
I kinda understand because of the whole engine break in period....although 15k miles sounds excessive. I've always been told that 5k is the normal break in period.
I've been tracking my gas mileage since 4000 miles and it hasn't changed at all between 4k and 32k miles.
 
Please log in or register to reply here.

Similar threads

S
    • Like
CX-60 MPG Review
Replies
1
Views
1K
RUDY7
R
M
Stuttering while lower RPM under load
Replies
0
Views
974
Meppen
M
S
Average MPG less than 20mpg, am I alone?
7 8 9
Replies
176
Views
23K
jadmt
jadmt

Latest posts

Back