[hoodrych]

Hey all,

I know there are several threads on this but I looked at them all and couldn’t get a solid answer/comparison.

Is anyone else getting really poor mpg? I did several full tank tests on comfort mode and sport mode and I’m getting around 22 and 18 mpg respectively. I’m coming from an e92 m3 so I was expecting a bit better performance near the advertised 26/30 mpg. It’s just weird that in sport mode I’m barely getting more mpg than my previous v8 car, which was a constant 16-17 mpg.

During my tests it was like 70% highway 30% city driving. Accelerations were linear and not aggressive. All tires inflated to 38 psi and there are no significant codes.

Car is 2020 with 17k miles. Any ideas on what could be wrong or is this normal? I don’t think it should be a big ask to get the advertised mpg.

Thanks in advance

[zazzau]

A screen shot might be helpful. Also is this on a 330i or M340i?

[hoodrych]

Originally Posted by zazzau

A screen shot might be helpful. Also is this on a 330i or M340i?

M340i. I will grab a screenshot tomorrow.

[peelerec]

Originally Posted by hoodrych

M340i. I will grab a screenshot tomorrow.

I can easily obtain 30-35mpg when Highway driving in sport mode.
Was the car ever tuned? Is it tuned?

[LPTyler]

I’m getting much better. Low to high 30s on my m340i. I made a 45 mile trip to work the other day and got 41 mpg on the way there ( slightly downhill) and 34 on the way back. If I drive it like it’s fun I get mid to low 20s.

[Soul_Glo]

You guys using premium? For example, I noticed an improvement with chevron techron.

OP was this a sudden drop or gradual? If sudden it doesn’t sound right. Could be anything from bad fuel pump, blocked fuel filter, to bad spark plugs.

[jiimmmayyy]

Originally Posted by Soul_Glo

You guys using premium? For example, I noticed an improvement with chevron techron.

OP was this a sudden drop or gradual? If sudden it doesn’t sound right. Could be anything from bad fuel pump, blocked fuel filter, to bad spark plugs.

Pump gas with a higher percentage of ethanol can drop the tank range pretty drastically

[whofelt]

highest i got was 440 on the tank in comfort, if i drive in sport mode, my mpgs drop pretty drastically as the rpms are much higher and shifts constantly. 90% highway and 80mph average speed.

[Soul_Glo]

Originally Posted by jiimmmayyy

Pump gas with a higher percentage of ethanol can drop the tank range pretty drastically

Yes it can. However, when things are clogged up due to short runs/cheap fuel it can help sometimes. Worth a shot I think in terms of DIY diagnostics.

[hayko_M340]

Originally Posted by Soul_Glo

Yes it can. However, when things are clogged up due to short runs/cheap fuel it can help sometimes. Worth a shot I think in terms of DIY diagnostics.

I wouldn't worry about it, averaging 21-22 mpg over the last 40K miles can't even remember the last time I reset it if I ever did. Mix of uphill roads, freeways, you name it. Car is tuned as well 32psi all around. When I want to it'll get either 150-200 miles to the tank or 400-450 depending on how heavy of a foot you have. Comfort majority of the time with short runs in sport + works well for me. If you're commuting long highway trips eco with coasting when it drops into neutral will get you that 30+ mpg and almost 500 miles range per tank, done it before.

[hoodrych]

Wow, yeah these replies definitely have me feeling like something is wrong. I’ve attached a photo of my current tank of 232 miles only getting 22.4 mpg.

I’m due for an oil change so maybe I’ll have them check the spark plugs. Can’t think of anything else.

And no it is not tuned.

[zazzau]

Perhaps change to Date since last refuel? That’s how I have mine set. Gives me a more realistic take on consumption. Though that might not make much of a difference in your case. Def have it checked out during your next visit.

Have you taken any long highway drives yet? Typically get in the high 30s on long trips.

[BigKutta]

I've never measured it, but last weekend I had a bit less than 3/4 tank of fuel left in my 330xi and i had a road trip coming up the next day. I figured I'd refuel along the way somewhere. However, I completed a 360 mile road trip (including stop and go highway traffic) and still had gas to spare. That really surprised me to be honest. Maybe my M2 has lowered my expectations LOL

[Emily172013]

Highway driving gives me between 32 and 35mpg.
Better than my 228hp 4cyl Audi Q3.

[peelerec]

If you have a heavy foot, especially accelerating from a dead stop drastically affects the city mpg. If hwy driving and cruise control or even steady pedal input at 65-75mph can easily net me high 30's mpg. I normally fill up with 91 Shell V Power ( CA ).

[Rawhide]

36 MPG on the highway in eco mode. Like Jekyll and Hyde.

[oonowindoo]

i average around 23mpg. 80% highway. Mostly in comfort.

Nothing is wrong unless you count your right foot.

Now if you take a long trip with little to no traffic and still average 23mpg, then maybe there is.

[TakeshiJin]

Originally Posted by hoodrych

Wow, yeah these replies definitely have me feeling like something is wrong. I’ve attached a photo of my current tank of 232 miles only getting 22.4 mpg.

I’m due for an oil change so maybe I’ll have them check the spark plugs. Can’t think of anything else.

And no it is not tuned.

Honestly at 22.4 mpg at 22.9 mph your doing way better then me lol. I get anywhere between 20-21 mpg in eco mode with those. In reality I only really get the avg combined mpg of 25-26 if I am in eco mode all the time. Highway cruise down eco at 80-82 mph on I-5 leads to a 33.4 MPG avg. So highway cruising is essential for better gas mileage. Also original owner of my car never coasted (0.1) with an avg of 20.8 mpg and with my 26.9 avg of owning the car for 3.5k miles only brought the avg up to 21 mpg. So drive mode matters, right foot modulation matters, and driving condition matters. If you want the best mpg you gotta give up the some acceleration fun.

[indabahamas]

I have a 2020 330i xdrive and was consistently getting over 40mpg’s in eco pro on the highway and on my last road trip which was the same as the picture below I could not get above 40. Since then I have been paying attention to it for the last two weeks and am getting 5 or more mpg’s less than before. Tires have the correct pressure so when I take it in for service soon I will ask them to check all the usual suspects. I will add an update if I find out what caused my sudden drop in mpg’s.

[billnchristy]

My avg speed is in the high 20s low 30s and I run 24-26 average. I have some nice highway areas that get me back up but the last 5mi of my journey are "city" and take over half of my commute time. 20min to go 15mi, 20-30min to go 5.

[Benjamin_Nicholas]

It's a sports car. What's gas mileage?

Some of ya'll forget what kind of car you bought.

[bavarianride]

My 2021 330i routinely gets 45+mpg on iDrive, or around 42mpg@pump on highways. City/suburb driving is around 26-28mpg.