[lux.sh]

Observed gas mileage for past 3 months. I was wondering why I had to fill up gas so much faster now, but that was answered via readings on the computer. I was getting 15.8mpg on average. City/Highway/Crazy ratio of 75/20/5. I wouldn't mind that if I was driving a lambo, but this is a friggin' sports compact sedan. I checked the tire pressure and cleaned out the air filter last night. While I didn't see any improvement yet(I wouldn't know), I'm pretty sure it won't do much.

My question is, what components of the vehicle contributes to gas mileage? Any simple maintenance routine you can do by yourself? What about stuff worth going to a shop to? Keep in mind, I haven't done any routine maintenance recommended by BMW. Last thing I did was basical check-up done by local repair shop when I was getting my coils/plugs replaced.

Any opinion, knowledge appreciated. Thanks.

[edirtaynine]

our cars suck ass on city mpg.

[berserkerx]

Make sure youre not carrying a lot of unneeded stuff around in the car. Go to fuelly.com. there are a bunch of tips on that site that help you out. I run bg44k through every tank before an oil change and bg cf5 half way through an oil change every time. But getting rid of weight filling up with good fuel (preferably try to find non e-10 fuel) and go easy on the gas pedal.

[fdriller9]

Try fuel injector cleaner.

[lux.sh]

I remember doing a research on fuel injector cleaner..
there was too much debate and no verified scientific data.
Anyone actually gained MPG through use of fuel injector cleaners or any similar products for that matter(deposit cleaner, etc etc)?

[micah_675]

Originally Posted by lux.sh

I remember doing a research on fuel injector cleaner..
there was too much debate and no verified scientific data.
Anyone actually gained MPG through use of fuel injector cleaners or any similar products for that matter(deposit cleaner, etc etc)?

No one gains fuel mileage from fuel injector cleaner. They do GAIN back what they have lost to carbon build up on your injectors, valves and possibly cylinder walls. That being said if you have never used some, I would run 2 back to back of each other. Carbon builds up naturally in a motor, it will clog injectors causing them to spray improperly. Which causes the fuel to not disperse properly into the air, causing a poor fuel to air mixture, which causes improper detonation, which causes mileage loss.

Also what kind of gas are you using?

[lux.sh]

I switch back and forth between Chevron and 76.
I'll try the fuel injector cleaner for my next oil change.

BTW, I went on a 10 hour highway trip today.
No scientific data used, but here are best details I came up with.
-95% highway, 5% city.
-Speeding varied between 60mph ~ 110mph. Averaged 85mph overall.
-Some high-rpm driving here and there during the highway trip to keep my self awake.

Averaged 29mpg through 2 fill-ups according to the computer.

How is this compared to most of you?

[DLE]

In my XI I average about 26.5, haven't really calculated in by pencil and paper but that's what my computer tells me.

[Denny347]

Originally Posted by lux.sh

I switch back and forth between Chevron and 76.
I'll try the fuel injector cleaner for my next oil change.

BTW, I went on a 10 hour highway trip today.
No scientific data used, but here are best details I came up with.
-95% highway, 5% city.
-Speeding varied between 60mph ~ 110mph. Averaged 85mph overall.
-Some high-rpm driving here and there during the highway trip to keep my self awake.

Averaged 29mpg through 2 fill-ups according to the computer.

How is this compared to most of you?

I get about 23 or so in city driving and I got 33 during my last interstate road trip. Odometer is at 76k

[lux.sh]

E90 330i is rated 30MPG on highway, correct? I'm just thanking god that it at least did close to average. I used to get like 33~mpg (computer based) before 50k miles..

Denny, your ride is obviously doing very well for 76k. What other maintenance have you done?

[willie55912]

This is dead on with my 2006 325xi. This is good mpg. I would suggest also using a injector cleaner. BMW used to recommend Techron....I do not know if they still do. I also have had great results using Sea Foam, but it is expensive..but I had an Audi to 389,000 miles with only one set of injectors in it when using Sea Foam every 30K.

[Denny347]

Originally Posted by lux.sh

E90 330i is rated 30MPG on highway, correct? I'm just thanking god that it at least did close to average. I used to get like 33~mpg (computer based) before 50k miles..

Denny, your ride is obviously doing very well for 76k. What other maintenance have you done?

Techron fuel injection cleaner just before the trip and I had the transmission filter and fluid replaced over the winter, that's it. I need to swap out the plugs here soon. I was getting about 500 mi on a tank of gas on 100% interstate driving using the cruise control.

[lux.sh]

Alright guys, I'll finally try the techron fuel injection cleaner.
Which procedure did you guys follow? There are so many debates over it.

Denny, 23MPG city sounds a bit high, no? Maybe we just have different driving style..
Speaking of tranny fluid, damn I need to find $300 laying around somewhere.

[axis]

I can't get anywhere near the advertised 20 city. My daily commute to work is about 6 miles on the interstate, maybe 3 or 4 miles in the city and I average like 17 MPG. If I do ALL highway, then I get 27-30 MPG. City is just terrible though. All city and I'd probably be around 15 or less.

My car has 64k, and I have replaced the plugs, coils, air filter with a K&N, charcoal delete, cleaned the MAS, and have used the techron cleaner a couple times.

[ska///235i]

i hear u on mpg...ppl here on this forum always claiming 30+ mpg on both city & hw, i call BS unless they have a diesel

[Express]

i get about 23 combined.

[LaLakers91tc]

I get 21 combined, max I have seen on high way trips is right around 30, and in city only, I can drop down to ~12-15 depending on how heavy my foot it.
For some reason, these cars are just exceptionally bad in the city.

my car has 89k miles on it, and I use a bottle of chevron fuel injector cleaner, or Lucas injector cleaner on the tank before each oil change, beginning around 60k. I just replaced the spark plugs too, and all my filters are cleaned regularly.

[fdriller9]

Originally Posted by axis

I can't get anywhere near the advertised 20 city. My daily commute to work is about 6 miles on the interstate, maybe 3 or 4 miles in the city and I average like 17 MPG. If I do ALL highway, then I get 27-30 MPG. City is just terrible though. All city and I'd probably be around 15 or less.

My car has 64k, and I have replaced the plugs, coils, air filter with a K&N, charcoal delete, cleaned the MAS, and have used the techron cleaner a couple times.

Yea when I'm in philly it's about 15mpg for me.....and that's on the high side.

Back home in Jersey, it's less stop and go traffic, but I'm still only around 19mpg.

I have a heavy foot...

[Express]

the only thing that goes in my gas tank is gas. injector cleaners can suck it.

[lux.sh]

jesus... I guess mine wasn't so bad. It seems like my City/Highway mpg is average after hearing from you guys.
I can swear this car had great gas mileage before 50k........... what the hell happened.

Originally Posted by LaLakers91tc

my car has 89k miles on it, and I use a bottle of chevron fuel injector cleaner, or Lucas injector cleaner on the tank before each oil change, beginning around 60k. I just replaced the spark plugs too, and all my filters are cleaned regularly.

Did you see any difference after 60k when yous started doing those maintenance items?

I wonder if alignment could change things. I heard it does effect gas mileage to a some degree. I haven't done any alignment for 70k miles. I'm pretty sure my 330i's alignment specs are pretty off.

[Cygnusx1]

330xi ..21 combined rural roads. 33 pure highway. 17 city. I drive easy most of the time. 53k miles on the car, well maintained. If you run non RFT's make sure you are running 38-40 psi in the tires.

[lux.sh]

Originally Posted by Cygnusx1

330xi ..21 combined rural roads. 33 pure highway. 17 city. I drive easy most of the time. 53k miles on the car, well maintained. If you run non RFT's make sure you are running 38-40 psi in the tires.

Non-RFTs here, 36F / 38R.
I think 38~40psi all around seems a bit too high?