I have only had mine for two weeks, but I drive the same interstate route (74 miles each way) for work. All I can squeeze out of mine is 25-26mpg with the 2.2L, cruise set at 73mph. Sure thought it would be more than that :{

 

FJRacer is right, aerodynamics matter. That's why a Prius looks like it does. Our little retromobile has retro 'brick' styling. There's only so much you can do with a blunt nose and vertical windshield.

 

29.1 MPG according to my dash computer. 2.4 Llitre HHR 2LT
I usually average 17.5 overall MPG

 

Take another profile look at the windshield, it is very laid back.. They are many other vehicles much less aerodynamic..

 

Just completed 3700 miles from Minneapolis to seattle up to Vancouver and back by way of Banff Got 30.3 mpg for trip mostly highway driving from 60 to 80 into a strong wind(which really hurt the final mpg)

 

On my third tank of gas since purchase. AVG-317 Miles- 13.3 gal.
Computer says 25- Math is closer to 24. 70 city 30 other. I do top off but these #'s have been the same give or take a mile or 2 and a tenth of a gallon or 2 on three tanks.

2009 LT just turned 30K tonight (1069 miles under my ownership and enjoying the ride!!)

 

Im getting a 2.2L 2010 HHR LS (manual trans)... what can I honestly expect? I was hoping for more that what I'm seeing... I'd like to see more 30's

Actually. Some of these numbers are abysmal.

 

Computer states 34-39+ on flat highway with cruise control 55-60.(1900 - 2K RPM)

City driving can kill any cars MPG - with low speeds, sitting at lights idling, warm up winter etc.

I like to use instant setting at times - It is interesting to see how MPG can be controlled when you can see the readout.

2009 LT Auto

 

I warm up car for 10 minutes so I can drive to work for 8 minutes, than same for home. DIC says 16 mpg and I'm happy.

 

Well I don't know how you all are getting that kinda milage....when I am on the interstate cruising at 75 my DIC is showing 22-23MPG.... 2.4L 5-speed with cruse control on all the way ran 350 miles today and best I saw was 24.2 for a few minutes. My HHR has 50K on the clock....tune-up time?