11hhrlt

Hello,
New owner, first time poster. And temporarily obsessed with everything HHR.

After @ 500 miles of use and 44k on the odometer, I was awfully bummed to notice my gas mileage is terrible (one of the reasons I bought the HHR was because of the supposed economy). According to my calculations I'm getting 21.3 in gentle, mixed driving. And the computer is pretty close with 20.8. Not at all good.

My first thought: the air filter. To my satisfaction, it appeared as though the filter had never been touched (very dirty). I put in a new one today and we'll see...

Changing my HHR's air filter definitely lived up to it's infamous reputation.
I read the how-to here and it was a big help but would like to add a few details: after making all the necessary disconnections I tugged... and tugged. No way it was coming off. I decided to tackle the bolt holding down the leg at the left/lower/bottom of the filter housing. It's not easy to get at but disconnecting it did the trick (the bolt has found a new - and permanent - home in the glove box). Also, if you do this job, be careful of the lower lip of the filter/engine shroud. It's razor sharp. Got a nasty little paper cut after slicing through a rubber glove. Consider hitting that with some sandpaper beforehand. I put everything back together with a little petroleum jelly (great suggestion from another member) and it slid right into place.

I'll report back after a tank of gas. Hopefully the new air-filter will change things for the better.

843de

I think you'll see a marked improvement, plugged or "super overdue" for a change air filters basically starve the engine making it less efficient as it labors to pull in an intake charge.

And yes, HHR's have the worlds most secure airboxes, this first time you change the filter it makes thoughts of stealing the Mona Lisa seem easy in comparison.

Oldblue

Welcome to the site!! go one set at a time!! next may be a good idea to clean the MAF sensor.

11hhrlt

Hmmm... Stealing the Mona Lisa, eh? Now there's an idea... (With my luck, the Mona Lisa will suddenly go missing).

Yes I am hoping for a really, REALLY "marked" improvement. Time will tell.

11hhrlt

Thanks Old, it's my pleasure to chime in. I'm liking my HHR. Just have to get some bugs out of it. Thanks for the suggestion re the MAF. Will follow up on that.

Oldblue

You're welcome, make sure you use Sensor Safe for MAF sensors and not Throttle body or carb spray!!

donbrew

My 2011 is getting kind of bad mileage in this cold weather for some reason also. A new air filter improved it a bit. When I do "mixed" driving mostly local, by time 21MPG is about what I get. All highway with cruise control at 65MPH (under 2500 RPM) near 30MPG, once I go over about 2300 RPM the MPG takes a nose dive.

jerry455

my 09 2.2 auto is down to 21.5 mpg right now. We have had -10* F and I have remote started my car lately for about a minute while I am walking up to it. The blizzaks don't help either. I typically lose 3-4 mpg in the middle of winter from the 26-27 mpg that I get in city driving in the summer.

11hhrlt

Update: after 235 miles of various driving conditions but still gentle on the pedal, my mileage has gone from DIC 21.3 mpg to DIC 26.5 mpg (very good but I'm shooting for 28, maybe 29). The first time I calculated the DIC was running behind my manual calculation. This time they were both exactly equal.

The air-filter change absolutely made a difference. I also ran the tires with a few pounds of extra air. That may have helped.

Next step: clean the MAF and see what happens.

Final note: It appears the more air, the better. But it seems also there's a pattern of poor gas mileage in (very) cold weather, as mentioned in previous posts. Has anyone considered the idea of introducing warm air into the air box? That could easily be done
via the exhaust manifold.

donbrew

Give it a try. Generally speaking cold air is supposed to be better. I wonder what would happen if somebody tried messing with the ambient air temp sensor. There are 2 air temp sensors, 1 ambient (near the front grille, depends on year) and 1 intake (part of the MAF)