I just pulled my 600 lb Harley on a 330 lb trailer from Michigan to florida and got 24.8 mpg at 70+ mph.

 

I really don't know about your trips, but I know that when we lived near Aurora(more in-town) and my wife drove this car, we averaged only 17-18MPG. Our previous car, a Grand Prix usually got 16 or so MPG in those conditions. I could see how in a slightly worse situation, with shorter trips, 15.3MPG might not actually be a problem. Have you ever just taken a highway trip to see how it does? That could go a long way towards finding if it really has a problem.

Edit: I also noticed that Consumer Reports found that in their testing, the HHR only got 16MPG in pure city driving. They suggested that it could get 23 in mixed driving, and 33 on full highway driving.

 

Wow this is a hot enough thread that even I, after MANY months of inactivity have to toss my .02 in. 1st things 1st:

07 Premiere Edition 2.4 Auto (the nicest looking car I've ever owned)
Stock except for Progress sway bar
Socal car with about 7200 miles.
36 PSI following recommended door sticker

I'm currently getting 23 MPG on DIC, CALI winter regular gas with mostly city and some FWY miles which in the LA area (as in most urban areas thruout the US) is as bad as driving streets. I'm not driving much since work is still slow following the slowdown from the Writer's strike, but it's still the usual mix as described above. I too find the DIC close enough to my hand calcs that I always look at it. I reset trip A and let trip B run to about 1000 before I reset that. The idea being the DIC is tracking the MPG in 1k increments...whatev! Inadvertently I found recently that I'm using a technique called "Hypermiling" (google it) where anytime I can and I think it's safe, I coast, keep the RPM below 2k, and turn the engine off at long lights or any drive thru. I even turn the motor off when parking BEFORE I raise the window or close/open the Sunroof...power w/o engine assist, a great HHR feature. I never warm up the car, a socal luxury you might think. This has become a habit of mine since out here Reg is almost at $3.50 a gallon at the cheap stations...not cut rate crap but the best deal local Chevron/Shell...and I'm pretty sure we will be the first to see $4 this year AND $5 next year!! So I am motivated to be this Hypermiler by default I guess. It really seems a shame that the struggling US big 3 cannot seem to come to grips with producing cars that have appeal and efficiency. They have in there combined Histories produced vehicles that were popular and efficient so they CAN do it, but somehow they just are not doing it now. And I don't mean Hybrids, which BTW are not currently selling well anyway...since they look like KEERAP. As far as the OP, he may have been confused by a lot of the claims here and in official lit...though GM et al can only claim fairly realistic MPGs on the window sticker these days esp. since the new regs went into effect. I've read some of the mileage claims here and scratched my head...talk about Hypermiling, I just assumed they coasted everywhere. In closing I would refer the OP and others to my recent pipe dream of finally owning a Miata, preferably a Mazdaspeed. Now this little creampuff is probably one of the lightest 2 seaters on the road. It is turbo, and a 6 speed and after all is said and done might be lucky to get 21 MPG around town...you'd be lucky to see 23 even with Hypermiling and a lot of short shifting, something I did with my SVT Focus a lot (trade in for my HHR, i miss it hence the itch for a MSM). I would advise the OP to be vigilent on checking the less than obvious factors, for instance if I'm not mistaken he said his tire pressure was 32...4 PSI below the door sticker spec of 36. That's some extra friction he's dragging. Don't scoff at this too much, I ride a Hi end road bike for exercise and my tires are usually at 115 psi and I CAN tell if they're at 110, you can definitely feel the drag so it should be a consideration. The other factors have been discussed here re. Octane, but that should be investigated over a period of time to. I'd switch for awhile to see...though I've not noticed a big difference out here running reg only...maybe only 1 mpg. I'm a believer in running SYN oil, where my notes showed me a solid 2 mpg out on the open road...again friction issues addressed. At the end of this tale there is probably NOT a pot of gold for the OP and indeed he may have to take a loss on this vehicle and do a bit more serious homework to find a vehicle that satisfies his expectations. As I've said above this is unfortunately not easy even in this climate of rising energy prices and slow responding auto makers. I wish him luck and condolences...owning and operating a vehicle in modern America OR the world for that matter is not as much "fun" as it used to be, except that when I walk up to my CFM Premiere Edition HHR I say to myself "damn that is one sweet looking ride!!"

 

I have been averaging 26 mpg since getting down to Florida and that is with some very slow city driving and with the A/C on.

 

just got 25.7 in mixed driving DIC showed avg of 33 mph 780 miles on the trip.
Local grocery store gives gas discount so I wait until I can get FREE 30gal of gas. I wanted to see how far I could go on my 30 gal.

 

So... would anyone care to offer an explanation why DIC reported 33 but his mileage was 25.7?

Vinny, are your wheels/tires stock?

 

He reports 33 mph average, not 33 mpg.

Yves

 

I have a 07 with a 2.2 Auto and Im averaging around 25.6mpg right now with the mix of city traffic and the small 2 mile stretch of highway i get on. I have installed the CGS cold air intake, Magnaflow cat-back exhaust, and now the stage 2 JetPerformance chip on my car. I drive it like a hot rod. My name is heath....so my kids call its Heath's HOT ROD!!!.

Remember to reset all your functions on your DIC to get a accurate reading.

So relax and enjoy the cool ride, but be real. its NOT a GEO METRO.

 

Just took a 4000 mile trip on mt 2lt 2008 bought in Dec & got 27.5 total miles on car is 4400 just barely broken in. I don't think that is to bad.

 

Sigh, still right around mid to high 15MPG, all city, average speed 20 mph, correct air in tires, 1500 miles. Shes goin in at 2000 for a reflash. It KILLS me to see others with such great city mileage although I am happy for them.