as of this past month or so, my gas mileage has dropped a bit. i used to get around 30 mpg, and it's down to at the best 27. i haven't been riding her any harder than usual (if anything, i've been goin easier on her). my plugs/wires are all new as of this summer, air filter is clean, air pressure in the tires are good, i've been letting her warm up a little before going anywhere since it's been quite cold the past week (and snowing), and she's not throwing any codes.
so, any ideas of what could be wrong would be helpful so i know what to try to do to get her running better. i know one thought would be a bad O2 sensor, but as i said, i'm not getting a check engine light at all. i do need new rotors and brake pads, and the oil needs changed again, but this shouldn't effect the gas mileage should it?
thx in advance for any help i can get.

oh, and i guess just for specifications incase any of this would be any help to diagnose a problem, she's an 02 2.2L fire with 61k miles...

My car does the same thing in the winter time. Best I can think is that with the colder weather, the air coming into the intake is denser, therefore requiring more fuel to get the proper A/F ratio.

The time between oil changes can impact MPG. Best to stick to the 3mth/3000 mile change schedule.

Since you've been letting it warm up a bit, you've been getting 0mpg every morning before you get in your car. And, as Kardain said, in winter your computer gives more fuel because the intake charge is cooler, and especially on cold starts, the computer runs rich (on the choke) anyway.

Eh, it's normal. My gas mileage sucks at the moment too.

atleast i'm not the only one...as far as the colder weather, i had thought this may be a major impact, and while it still may be, my car started doing this before it got this cold...i mean, it was like stil around 65 degrees and the car didn't need warming up then. i don't know, i guess i'll get the oil changed and see how that effects my mpg now...thx guys.

Okay where to begin.

One dont let the car idle in the morning, it can be 15below zero as soon as the ait big light stop flashing its in gear. Heats up a lot faster driving down the road than letting it sit there and piss away gas.

Now I know a bunch of whiney bitches will say, its not good to do that. Bull@!#$ it aint, it is bad to let it there.

Secondly all states in the colder climates are using the winter blend gas, that does decrease mileage.

Your car is also in open loop longer, takes longer to heat up.

As for the colder air is less dense, density of the air has nothing to do with gas mileage, density of the air does have to do with power though.


Oil changes dont really effect gas mileage to much, unless its really bad like 8k than it isnt the problem. The reason people believe this myth is because Jiffy Bastards started saying that BS.
Make sure your using the correct weight, using the wrong weight like 10W in a 5W engine will decrease mileage, more friction engine has to work harder.

Lots of things can cause bad mileage though, seems 27mpg isnt to bad right now, I wouldnt think so.
I'd just wait till spring see how the mileage is then.






- 2004 Cavalier - 124k, owned since new

thanks alot man. thinking about it, i forgot about the winter blend gas...i guess i never worried about gas mileage before anyway. =P this makes me feel better about my car.

Quote:


Secondly all states in the colder climates are using the winter blend gas, that does decrease mileage.

Your car is also in open loop longer, takes longer to heat up.

those were my two ideas. The only potential problem with not letting the car warm up would be the load on the engine as its cold. Either way your car is going to run cold.


<img src="http://img.villagephotos.com/p/2003-11/504808/z28.jpg" width=317 height=59>

if you are running Synthetic starting up the car and driving is not to much of a problem. If you are using conventional oil then warming up is a good idea so that the oil can warm up a little before hitting the road. Some of us don't get winter gas because we don't live way up north but we still get cold weather which make my gas mileage drop in the winter, by about 2-4mpg and i don't drive my car hard.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

I don't know if everyone already knows about this or not, but there's something that I use/sell that works very well in increasing your gas milage. This is actually one that works, and is guaranteed to work, but it's a gas additive. It gives me 35 mpg hwy and about 28 mph city (I calculated about 60-80 bucks savings for one bottle for me) with my 2000 z24. If this interests anyone email me or let me know on this.

Rob S wrote:........One dont let the car idle in the morning.........
.......its not good to do that. Bull@!#$ it aint, it is bad to let it there......
As for the colder air is less dense, density of the air has nothing to do with gas mileage, density of the air does have to do with power though.

Let your car idle in the morning, it is better than just driving it. Synthetic oil helps.... Colder air is more denser than warmer air, which requires slightly more fuel to maintain same A/F ratio.

Quote:

.... the air coming into the intake is denser, therefore requiring more fuel to get the proper A/F ratio...

Very True.

Winter gas with the extra additives does not help gas mileage wither. You are also running more electronics normally like defrost, heater, wipers, and lights. Also driving through snow eats more gas then driving on a clean road.







PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

Rob, (Sigh) Please if you don't know don't say anything. The state of MD has done away with its use of oxygenated gas for the winter time siteing no noticeable reduction in harmful emisions but that the re-formulated gas had been shown to reduce mileage.
The gas in use here in MD is the same regardless of the time of year. This was done YEARS ago here and other states have followed suit.


Now for the REAL reason (not just one I'll make up) Our cars do not have a choke. They are fuel injected so unlike older cars the only way to richen up the mixture is to increase the amount of fuel being sprayed into the engine. This is why the mileage drops when its cold outside this is aslo the reason why if you buy one of those resister things to give you more power it won't. All you've done is made the computer think the incomeing air is colder so the computer richens up the mix. So unless you're takeing in more air too it won't give you any more power.




Semper Fi SAINT. May you rest in peace.

^^^ What he said. . To many people come on here and give information as if ti was fact.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

Thanks Mylife75.




Semper Fi SAINT. May you rest in peace.

^^^^^

Now how in the World would I know what the state of Maryland is doing with their gas? Lets see I dont live anywhere near there, I dont plan to visit there anytime soon, I dont read any Maryland news websites. Hmm I wouldnt know. I was wondering if you could tell me about recent things dont in Ilinois, laws anything off the top of your head?

Since winter blend does decrease mileage I figured I would toss it out there.

Now lets see what else.

I never said our cars have a choke, I made no comment about chokes. Where did that come from?

I never said anything about a resistor thing giving more power. Seems your just putting words in my mouth.


- 2004 Cavalier - 124k, owned since new

Well the comment about states useing winter blend gas would imply you actualy know what all the states are doing.

The whole thing about the choke was to illustrate WHY our cars use more gas in the winter months. Due to the whole fact that the computer feeds it more when it sees the lower temps. The risister thing was just to show the poor mileage in the winter can still happen in the summer IF you use one. Never said you mentioned either one of these things Rob. Didn't put words into your mouth thats why the were in a seperate paragraph.




Semper Fi SAINT. May you rest in peace.