hello ,

not sur if this is the right section for this.

i have a 2010 hhr , bought it with 32, 000 miles on it. when i got it , it was march of 2012. it came from FLA. was in a lease program down there. so it was very clean and well taken car of. i was getting 33/34 mpg but as winter got here it went down to 25/26 mpg. changed air filter but not much better. warm spring or 2013 it goes up to 28/29 mpg but thats it. winter of 2013 right back down to 25/26.

spring of 2014 back up to 27/28 mpg. now we have a cold snap comin and i notice it already started going back down to 27 mpg.

is there something different i need to do to te engine , since it was a fla car ? o2 sensor or change anything else on it because of maine weather ?

i know the car was bought in a action and trucked to maine. the sales man told me it just got there that week so it never saw a maine winter.

hoping someone can help me get that 33/34 mpgs back.

thank you

 

Several of us have noticed that cold weather affects the MPG significantly. Can't seem to find logic for it.

But the overall lower MPG may be attributed to different gas formulation. I know that if I buy gas the other side of the river here there is more alcohol in the blend which gives less MPG.

You also might be in need of new spark plugs, a throttle body cleaning, an ATF change, a dose of injector cleaner. You did not state the current mileage.

 

A few common things that have an effect on gas mileage:

1) Driving habits- Easy starts, coasting to stops

2) Ambient temperature- Colder air= more fuel consumption

2) Fuel quality- winter blend fuels are not as efficient as normal

3) Tire pressure- tpms should tell you (if equipped) If not, 30-32 psi in all 4

4) O2 sensors- Will trigger CEL

5) Mass airflow sensor-Will trigger CEL

6) Built up deposits-deposits can mean a loss power or wasted fuel, but under 100,000 miles you likely don't have an issue

 

No offense, but getting 27/28/29 mpgs in mixed driving seems about the norm based on other posters on this site.
Getting 33/34 in mixed driving would be above normal. Again, based on other posts I've read.

Just an observation.

 

32 MPG all highway at 65 MPH is about right. Around town only about 26 MPG.
Oddly enough exactly what the EPA estimate sticker said.

Not to mention the relative terrain. FLA. no hills. ME. lots of big hills. I can see a big difference on long trips between VA. and Upstate NY on the same tank of gas and cruise control.

 

Tuesday, I left Rochester, NY to head back to Florida. It was 34 degrees with rain all the way to Virginia and only got up to 40 degrees or so in Virginia. My 06 HHR was getting 29-32 mpg, no cruise because of the rain. Today (Tuesday) I drove from Virginia to Florida (13 hours) using cruise as much as possible and was still getting ~32 mpg. I set the cruise to the speed limit and seemed to be the slowest one on the road. I have a 2.4 L auto, so I believe driving style will effect mpg many times. My HHR turned 132,000 miles on this 2800 miles round trip.

 

All of my vehicles have always dropped at least 10% in MPG in cold weather. This past winter was especially brutal. Our old Trailblazer was only getting 11 or so all winter. The HRR only got about 21 in the city. We're back up to "normal" mileage now that temps are 40ish.

 

I drive a 2010 hhr it 2.4 and my mileage was consistently 26-27mpg since we got it 2 years ago and this last winter it started dropping, now it's summer and still dropping. 87 octane, Mobil 1 5w30 Mobil 1 filter new air filter, 2 factory tires(firestone) 2 uniroyal tires (last winter) 72k miles, 35psi cold, easy driving, no habit changes. I can keep it around 23-24mpg, but my fiance drops it like a stone, she drove last night and it dropped to 21mpg, her habits aren't bad either, and it did not go up with me cruising at 65 for 20 miles to work this morning.

 

A few questions:

1) are you one that turns the vent off (recirc mode)? Recirc mode automatically turns the A/C on.
2) do you have the defrost on? The defrost setting turns the A/C on.
3) do you regularly clear the Average MPG? If not the average will be weighted.
4)do you idle a lot?
5) do you sit stopped in traffic a lot?
6) has somebody changed the spark plugs? The OE plugs should get you at least 100,000 miles, somebody may have changed them with the wrong type or tried to gap them (that ruins Iridium plugs).

20 miles of highway driving won't show much in an average.

 

A/c on, always had it on in summer and still averaged 26-27mpg before now.
Recirc off, defrost off.
Cleared last week, didn't clear for months at a time before.
Not much idling nor stopped traffic, most of my miles are 45mph+.
I have not changed anything but 2 tires, front brakes, air and cabin filters and oil changes since buying it at 36k miles.

Last long trip was to Dallas, 80mph the whole way, no traffic when we went and it averaged 28mph...a far cry from our San Antonio trip when we first got the car which averaged almost 40mpg that trip until we hit heavy traffic, which dropped it to 32 average.

It bugs me because I got used to 26-27mpg, I had 2 blazers before this car and they averaged 18mpg for the 98 v6 auto and 22mpg for the 92 v6 5 speed, I was hell on both being a teenager/young adult.