So. It has gone from about 30 degrees to about 60 degrees over the last month. Snice I've lived in my new house (5 months) i've averaged 25.5 mpg. Over the last month it has increased to 26.5. Now, there are a few things that I can contribute to this.

1.) Chaning from the SS spoiler to the LS spoiler.

2.) The increase in gas prices has ligthen the wieght of my foot.

3.) Warmer weather = better gas mileage for the 2.0



my thoughts.

1.) should have a positive change in gas milage. But I dont think it it should be a whole gallon.

2.) dont think so.

3.) Best chance.


What do you guys think?

 

well, how long have you had it? gas mileage does get better the longer you have the car... when i first got my cobalt i was getting about 22 mpg, now i get more like 27 28 mpg

 

Switching from winter to summer tires could have an effect too. Not a huge one, but one none the less.

 

I bought the car in august. It has 15,000 miles on it. from miles 4,000 - 14,000. I averaged 25.5 mpg. Over the last 1,000 miles or so i've averaged 26.5. Havent switched the tires either.


I fill up about once a week.

 

damn im still only lucky to get 17mpg on mine but i only have 2700 miles on my car

 

this is normal when the weather gets warmer for mpg to go up. colder weather requires more fuel to heat the engine up causing lower mpg. as the weather gets warmer the engine gets warmer faster so your mgp will show. dont believe me just put a low temp thremostat in your car and watch your mpg go down

 

sorry but im getting the exact oppisite. i was able to stay in the 40's now its super hard and the regular for the mpg now is 37,38 ish. figure that heat robs my efficency. plus i live in the desert and hell always comes. you literally cant go outside in the summer between 11 am till 4 pm due to the heat and risk of uv"cancer bad".

 

Was 30ish and know 33ish but it is all relitive to were and how I drive. I can get 35 to 40 all on the same hyway and that is if I reset it during the best time to reset.

 

In cold weather, our vehicles take a much longer period of time to reach full operating temperature. And they take this extra time each and every time we start them up, even if they have not fully cooled down.

Modern engine-management systems are very efficient at optimizing the fuel/air ratio entering the engine. The oxygen sensor monitors the percentage of oxygen in the exhaust, compares this with the percentage of oxygen in the atmosphere, and generates a low-voltage signal that communicates this ratio to the computer. The computer then adjusts the pulse-width of the fuel injectors -- the precise period of time each injector is open on each injection cycle --to fine-tune the amount of fuel reaching each cylinder.

The system makes this very fine adjustment dozens of times each second, working very hard to reach the optimum air/fuel ratio for any given situation, and at steady-state cruise speed seeks to approach the perfect ratio of 14.7 to 1, called the stoichometric ratio. The system is running in a "closed loop" when it is relying upon the oxygen-sensor signal to fine-tune engine operation.

But the engine-management system can seek this optimum air/fuel ratio only when the engine is up to full temperature. In fact, the computer does not look for a signal from the oxygen sensor until it approaches full temperature. During the warm-up cycle -- which takes considerably longer in cold weather -- the computer operates on a warm-up program based on coolant temperature, mass airflow or MAP sensor input of air volume and temperature, throttle position and engine rpm. This is called "open loop" operation, meaning the system is not operating off the feedback from the oxygen sensor.

In open-loop operation during the warm-up period, the engine requires -- and is provided with -- a richer air/fuel ratio to ensure good combustion.

It needs this extra fuel for the simple reason that a percentage of the atomized, then vaporized, fuel delivered to the engine condenses into liquid gasoline on cold internal engine components such as the intake manifold, intake valves, pistons and cylinder. And remember, it's gasoline vapor, not liquid, that burns.

Until those parts warm up, the engine needs more fuel to operate with reasonable drivability. Thus, the colder the weather, the longer it takes for your engine to reach full operating temperature and closed-loop operation, and thus the more fuel the engine uses to deliver the same driving cycle. That's the primary reason your engine consumes more fuel in winter driving.

Another factor in winter mileage is air density, defined as the number of air molecules per cubic foot of air entering the engine. Remember that 14.7-1 air/fuel ratio? That means 14.7 parts of air are mixed with one part of fuel for the perfect air/fuel ratio -- that's a lot of air!

In winter, colder air means denser air -- more molecules per cubic foot. At any specific throttle setting or opening, the same number of cubic feet of air, but containing more air molecules, will enter the engine. The computer will provide more fuel to create the proper air/fuel ratio at that moment. This is a bit more subtle, since "more air/more fuel" produces more power, so you may be able to operate at a slightly lower throttle setting -- sort of rebalancing the equation.

 

Those reasons are good, but there is a real reason you are getting better gas mileage. I noticed you like in IL. During the winter months gas companies change the addatives in their gas to compensate for cold starts. They pretty much add more ethanol. Were regular gas burns at 14.7:1, ethanol burns closer to 11:1 A/F ratio. Therefore your car compensates for the different gas mixture to achieve the proper fuel trims. Spring is coming around now, so gas companies are switching back to summer gas. That is the reason for increased mileage.

 

I live in Oregon.
Here in the Portland metro area, we have to use winter fuel from Nov 1 to Feb 28. The winter fuel is oxygenated and contains alcohol. Up to 15%. At all stations. This is only true in the big city.....
When on winter fuel, the computer sees a leaner mixture due to the alcohol, so it compensates by adding more fuel. Alcohol contains half the energy (by volume) of gasoline.
The result is lower fuel economy. Typically 2-3mpg.......
This has been consistent for many years here, same result in my Olds FWD 442.

I was getting 23 (read from the DIC) during the winter, now I'm seeing 26.5. Actual mileage is about 1-2mpg lower than indicated.

Problem here is.....not all stations make the switch in the summer. They have the option to run the mixed blend all year long. So I called the State fuel inspector and got the skinny. What brands do what.
If there is a date range on the pump...that's what they have to do.
If it says "may contain up to 15% alcohol"....they can run that crap year round.

So I only buy Shell premium........I also use it in my Nova with excellent results.

MacG321 beat me to the answer! Good job.

Ron

 

Here in MI I get about 26mpg with 2800 miles on the car now. I have goten 31.6 on a trip from the west side of the state to the east side and back.

Later