bad gas mileage

AJules · 12-18-2007, 12:33 PM

I calculated my gas mileage for the first time today

and it's about 18.5mpg

I expect to be getting at least 25 because I do mostly highway driving and try to keep my rpms low.
and I haven't driven it any days in the snow

anyway, anybody know what could be causing this?

spyhunter · 12-18-2007, 12:36 PM

winter gas blend?

TheMeaningOfLife · 12-18-2007, 12:41 PM

Mine gets pretty bad mileage to, like i go through a 1/4 tank in like 3-4 days of easy driving about 15 AT MOST a day. Thats what about 40 to 60 miles for what 3 gallons of gas?

TheMeaningOfLife · 12-18-2007, 12:42 PM

double post, plz delete

billytheman1188 · 12-18-2007, 01:01 PM

DAMN, your getting shitty mpg with a 2.4? I know i get horrible mpg (about 15), but i have the 3.4..... anyways, during the winter a lot of cars get shitty mpg...... in the summer i get a little over 320 miles on a full tank, during the winter i get around 250.... the joys of owning a 3.4 alero ;-)

[ion] C2 · 12-18-2007, 01:20 PM

yes shitty mileage, around 20 now

Gr1m · 12-18-2007, 01:38 PM

im lucky to get 225 a tank

nickbain · 12-18-2007, 01:40 PM

how long do you let the car warm up in the morning and before you head on your way?

AJules · 12-18-2007, 01:44 PM

Quote:

Originally Posted by nickbain

how long do you let the car warm up in the morning and before you head on your way?

I don't it's garaged

billytheman1188 · 12-18-2007, 01:44 PM

I try not to let it run for a while unless there is a thick sheet of ice over my car. I get in, start it up and go..... i never drive crazy either, especially when i first start the car up, gotta let it warm up while driving :-)

[ion] C2 · 12-18-2007, 01:47 PM

i have to let mine warm up so the O2 sensor gets warm enough that the system goes into closed loop, otherwise i lean out

slalomking · 12-18-2007, 01:52 PM

A long lived thread here last year showed MPGs all over the board for Ecotec Aleros. Some guys were getting mid 30s on the highway, some like you were betting in the high teens. For the record, my automatic gets a consistant 21.8 locally in suburban driving, 23-24 pure highway.

I don't believe driving style differeces and winter gas can possibly account for the huge range of reported MPGs. I'm convinced there is a hidden QC issue in a critical component that GM and all of us are not seeing.

CBLOHM3400 · 12-18-2007, 02:18 PM

I thought that all o2 sensors past year heck i can't remember but i thought that they are all heated
but hey i might be blowing smoke

[ion] C2 · 12-18-2007, 02:25 PM

no they aren't, but you can buy some that are. all i know is if i just get in and drive my car runs in open loop on a preset tune, not taking data from the O2 sensor until it warms up a little. then my A/F ratios stay good, otherwise it just spikes over to lean and the car tries to die

misslindseysue · 12-18-2007, 02:30 PM

Heated O2's don't stay warm all the time - heaters turn on when you turn the car on. It takes less time than without, but still does take time to warm them up.

As for mpg... my 3.4L auto got 28mpg avg in the summer and 25mpg average in the winter - very consistently, only slowly dropping over the years (I had it 7 years). So winter blend fuel does decrease economy, and that's a scientific fact, supported by actual data.

AtomicX · 12-18-2007, 02:34 PM

I have a 2.4 and I filled up on friday, drove about 85 miles, down to just about a half tank today.

TheMeaningOfLife · 12-18-2007, 04:46 PM

Thats about where i am at.^^^

01silveralero · 12-18-2007, 04:48 PM

Quote:

Originally Posted by billytheman1188

DAMN, your getting shitty mpg with a 2.4? I know i get horrible mpg (about 15), but i have the 3.4..... anyways, during the winter a lot of cars get shitty mpg...... in the summer i get a little over 320 miles on a full tank, during the winter i get around 250.... the joys of owning a 3.4 alero ;-)

390 summer. 270 winter. thats with my 3.4

my 2.4 got like 27mpg up until recently now its getting like ~17.

CharleyO99Alero · 12-18-2007, 07:26 PM

***

My last couple of tanks of gas have averaged 25 - 26 mpg in local driving. I was getting 27 - 28 mpg a couple of months ago. Best I got was on a trip back at the end of July where I got 31 mpg averaging 70 mph. Now, my friends and family know me as a "lead foot" as I'm not the easiest driver around. So, maybe it is the gas reformulation.

But, if you're getting less than 20 - 21 mpg with a basically stock 2.4 then I'd say something is wrong somewhere. Check your spark plugs, coils & connections, and air filter.

***

Cliff8928 · 12-19-2007, 02:09 AM

Quote:

Originally Posted by misslindseysue

Heated O2's don't stay warm all the time - heaters turn on when you turn the car on.

Actually, yes they do stay on all the time. They are supplied power from the "ERLS" Fuse in the underhood junction block when the key is in the "Run" position and grounded through a splice pack at ground location G203.