poor mpg

[dhurst765]

i have a 04 ecotec with the origional plugs i think. i bought it off my parents for a dollar and i believe my dad hadnt changed the plugs and i only get 20 mpg in city and 27 highway any suggestions?

[heineck]

unplug the battery overnight,

[dhurst765]

that willl just reset my coputer right

[heineck]

yepp, i was only gettin 220 street and 300 highway, i reset it and got like maybe 15 better on street

[dhurst765]

i have to work tonight from 8 to 1am so when i get home i will disconect it

[CactusWill]

You're only off by 2-3 mpg tops, hows your driving habits, do you drive like an asshole? Even if you did, you should get at least 30 on the highway, so start with the basics, oil change, air filter, and the spark plugs you mentioned is a possibility too.

[dhurst765]

i just put a wai on oil change needs to be done and plugs i have 80400 miles on it

[CactusWill]

It wouldn't hurt to change the plugs but its probably not going to improve the mpg, I would look into other possibilities.

[dhurst765]

it also overheats at idle

[CactusWill]

Well then you've obviously got something else going on, you need to get that checked out.

[heineck]

forgot to mention that one

[Valley olds]

Are your fans working when it heats at idle? Also, when your car is heating up, is your AC on? Mine will also heat up a little at idle if I don't turn the AC on. Also, check for any lights turning on in your dash.

[Bmorezcmunee]

yeah could be the following:

clogged cat
o2 sensor
wires
coils

i know my car needs a whole new exhaust. my last fill up i only got 200 miles out of a tank!

[dhurst765]

im in the process of changing the dexcool out for the green stuf i have 75/25 water to antifreeze right now. it gets up to 3/4 hot until i start going and it doesnt overheat as bad if the ac is on. i also thought it might be my thermostat

[CactusWill]

when your car is heating up, is your AC on? Mine will also heat up a little at idle if I don't turn the AC on.
it doesnt overheat as bad if the ac is on


Whatever you guys are talking about makes absolutely no sense whatsoever

[heineck]

yea ur supposed to turn on the heat when your overheating LOL

[Valley olds]

I dont know, but I think that on my car, when you turn the AC on, it turns the engine cooling fans on as well. Several times its happened to me, that Im at idle with the AC off for a good while, and it starts to heat up. The moment I turn the AC back on though, even if I dont go and am still at idle, in less then a minute, my temperature will go back down to normal.

[colonel6632]

my car also starts heating up at idle when its warm out... it just goes between half and 3/4... so not to shabby, and my motor is about 6 months old.

and cactus... he isn't getting close for the ecotec. on the highway... i average 35-40mpg, and i only get about 26mpg city... but i drive her hard

[CactusWill]

and cactus... he isn't getting close for the ecotec. on the highway... i average 35-40mpg, and i only get about 26mpg city... but i drive her hard


Thats unusually high for an ecotec, especially if you drive hard, assuming that your calculations are correct. The epa ratings of 21-24 city, and 30-32 highway, are very close to real world mileage. I got 21-23 city, and 30-35 highway. Over 35 on the highway is an anomaly, and so is more than 23-24 in the city, which in your case is most likely not true city driving. More like rural city driving.

[dhurst765]

my mom told me when she had it she got 25 city but i also dont drive like her i am into it a lot

[CactusWill]

thats what I meant when I asked if you drive like an asshole

[dhurst765]

lol not really like an asshole but not like a grandma either

[CactusWill]

Well, 20 in the city isn't bad, I've gotten as low as 17-18 when I drove like an asshole, but you should always get at least 30 on the highway with an eco. I'd get that overheating thing checked out, its likely your problem.

[dhurst765]

i have thought it might be my thermostat or coolant fan sensor

[AleroDrime]

hey i went with the oem tire size 225 50 16 when i got my new rims but could the extra airflow of the new rims vs the hubcaps create extra drag and lower my gas mileage, i drive the car even slower then i did b4 now

my mod are rims and tires, cosmo intake, and eibach springs, i did all this at once and have gone from 27-29mpg to 25-26.5 mpgs

[Vic28]

hey i went with the oem tire size 225 50 16 when i got my new rims but could the extra airflow of the new rims vs the hubcaps create extra drag and lower my gas mileage, i drive the car even slower then i did b4 now

my mod are rims and tires, cosmo intake, and eibach springs, i did all this at once and have gone from 27-29mpg to 25-26.5 mpgs
LMAO i like how you talk about the "extra airflow", have you actually measure it?? I think is more due to weight, than that so called drag.

[AleroDrime]

ok airflow is a goofy reason, but whats bogging down my mileage, why didnt it go up with the cosmo???

[CactusWill]

What?

[AleroDrime]

why has my gasmileage decreased instead of increased

[darksobsession]

got bigger wheels? shift kit?

[ndottaylor]

Just wanted to ask since overheating was brought up... my fans dont kick on without the A/C being on... anyone know why? It gets up to the 3/4 mark and still no fans. so i just turn on the ac and it drops back down below the half mark.

[Valley olds]

ndottaylor:Just wanted to ask since overheating was brought up... my fans dont kick on without the A/C being on... anyone know why? It gets up to the 3/4 mark and still no fans. so i just turn on the ac and it drops back down below the half mark.

I think the fans are activated with the AC. Mine does that too.

[ndottaylor]

I think the fans are activated with the AC. Mine does that too.

that just sounds like a disaster waiting to happen

[AZFire316]

Sounds like a GM thing, my cavalier does the same thing, as does the camaro. The factory fan activation is set really high for some reason, but when the A/C is turned on, the PCM automatically turns the fans on.


Wow, just looked at the date of the last post, talk about resurrection.

[jlong]

Yeah it's an older thread but a good one. My gas mileage on my 2.2 auto is about 20 city 27 hwy.

One thing not mentioned here is the differential gearing. I believe mine is 4.10. Does anyone have the rpo codes for the gear ratio. I also have the stock steelies. Not sure how big the tire is, but it's the stock size too.

[ServO]

I think the fans are activated with the AC. Mine does that too.

Mine does this as well, but the A/C doesn't have to be on, it's just whenever I turn the fan up past like the 2nd or 3rd setting that the fans underneath the hood kick on.

[Nate's Alero]

my fasn do this as well, with the a/c on, they are both running... but it'll go to 3/4 and even higher...no fans...

PCM issue?

might just go SPAL fans, with Dual 12" fans, and a SPAL PWM

[AleroDrime]

I dunno I average 29 mpg on the interstate and the gps rates that at an average speed of 78mph, with a high of 93, i run hard and do fairly well

[Vic28]

So ppl think is not normal to have the Fans ON while the A/C???

[01silveralero]

I dunno I average 29 mpg on the interstate and the gps rates that at an average speed of 78mph, with a high of 93, i run hard and do fairly well

78 average speed and high of 93 wth is the speed limit there I thought speed limit is 70 there.

[AleroDrime]

it is but you run with the traffic on the interstate, witch is normally doing ten over, i racked up that 93 prolly either messing with those bikes, or dodging the sequia that was changing lanes with me in its blind-spot

btw i hate old pple who dont signal while changing lanes, does anyone else realize its a moving violation to change lanes with out signals???, yes i weave traffic like an idoit but i signal

[JLw7123]

ya it is annoying when people do not signal.

[jlong]

I hate when people speed up and slow down and when you speed up to loose them they follow.

[02AleroEco]

my car also starts heating up at idle when its warm out... it just goes between half and 3/4... so not to shabby, and my motor is about 6 months old.

and cactus... he isn't getting close for the ecotec. on the highway... i average 35-40mpg, and i only get about 26mpg city... but i drive her hard

i know i need a new o2 sensor and i think an fpr. but seriously tho 40 on the highway and 26 city??? i get like 18 city, and my plugs are new, fuel pump and filter are new. those two things shouldnt affect me THAT much right?

and the one in the engine by the header is the upstream correct?

[undecided02]

How is your coolent level?

[AleroDrime]

im sure thats a miscalculation, even though abhellrazor claims 38 mpg, The new epa ratings for our car is 21 City and 30 Highway, http://www.fueleconomy.gov/feg/findacar.htm Even though i just averaged 32 the other day, ofcourse i have my 51psi tires at 48lbs and a CAI and new plugs

Tips for impoving though, would be slow down and try to accelerate slower, stay ontop of tire pressure, and maybe run STP or SEAFOAM fuel cleaner every 2-3 months
read this (i think itd be cool if we could find that curve for our car)
http://www.fueleconomy.gov/feg/driveHabits.shtml
http://www.fueleconomy.gov/feg/maintain.shtml