sking1973

I have an '07 LT with 36000 miles and I get around 34mpg hwy usually. My wife has an '07 Fall Special Edition HHR with 26,000 miles on it. She is getting around 25mpg hwy. Any ideas where I might squeak out a few more miles? I changed out the air filter (huge pain in the a** I might add) and checked the tire air pressure (fine). She does all the highway driving so she really needs the most mpg. I told her I would swap cars with her, but she likes all the bells & whistles of the 2LT. Darn.

Greybeard999

She should be getting about 34 with a 2LT.... I do with mine. I get better mileage running 93 octane but was still close to 30 with regular..... 25 is too low.

XtremeModifier

Sounds to me she likes to use that hammer a little ... my best guess anyways. And with these WV roads, I'm not surprised; I average close to 27/28 with my 1LT/2.2L Ecotec, so with a 2.4L, it doesn't surprise me one bit. Trying to think of what you can do to further improve the milage, idk, maybe new plugs/wires, but idk how much of a PITA that is on the 2.4L.

- Jake R.

tplyons

I'm only at 26-28 MPG highway, but then again that's Jersey rush hour traffic and I've got a bit of a lead foot.

urbexHHR

I've never been able to get much more than 29-30 on the highway doing 70. Mind you this is taking it very easy. In fact, if I go 60, I can't get much more than 32-33mpgs.... This is with the 2.2

sleeper

Maybe the final gear ratio is deeper in hers. Just a thought..

Randy_W

My one longish trip, 500 miles round trip, I got 31.6, that was 250 miles relative flat ground, 190 in hills/mountains and 60 in town. On the flat stretch I got 35.6 as figured with odometer/calculator. My trip computer shows consistently 6-8 tenths less than I actually get, most vehicles I've owned with trip computers have over estimated mpg, this one under estimates. Mine is an '06 LT 2.4 a/t.

HeritageHarley

I have yet to get over 26 mpg with my '06 2LT.

Randy_W

Where and how we drive makes a lot of difference in mpg, also every vehicle is an individual, but that 26 figure would raise a red flag. I would check the 02 sensors, they can be bad enough to cause poor mpg, light throttle miss/stumble, etc... and not set a code for 15-20k miles.

Greybeard999

I did a little "experiment" yesterday wanting to find out if my switch to Synthetic oil did anything for this mileage deal..... This is not a "scientific" closed course experiment mind you, more of an observation for my own enjoyment.

A little background: Stock '07 2.4L auto, 3.91 final drive ratio. Euromax 612 wheels which are lighter than the stock alloys with Dunlop Direzza tires.(Tires at 33 PSI) I use the DIC as my gauge here which by the math reads about 1.5 mpg lower than actual. Reset the DIC right after leaving my driveway and leave it visible until I get back in my driveway. I run Sunoco 93 octane which does net me higher MPG as well as better performance.

The route: a combination of 55 MPH Ohio back roads (the 309 speed trap) and route 23 which is part 65 mph, 55 mph, and some 45 mph stop and go. A short bit of "city" driveing on each end of this route. Round trip is just over 88 miles. I go down to visit my Father every Friday so time and traffic are pretty much constants here except for an occasional pass on the back road if somebody can't get up to speed..... Roads are not flat, there is mild rolling hills and a 150 foot difference in elevation between my Fathers place and mine.... No not WV but also not Kansas.

Weather: was about the same for both of these runs, in the 80's, clear and dry, AC off. I go down about 9:30 AM and come back around 3:00 PM. Driver's and passenger's side windows open as this is normally the way I roll (more drag which should hurt mileage)

First run: About a month ago I did this route, right after I put the new air filter in and during that test I used the cruise control exclusively, meaning for accelerating back up to speed after a stop..... light accelerate to 25-30 MPH and push resume..... Hypermiling if you will. (this really pisses people off ) I always use cruise for setting my speed at the speed limit anyways.... cops around here have no sense of humor I did not pass anybody on the two lane back road during this run.....

Second run: Yesterday everything was pretty much the same accept I accelerated hard several times (WOT) and normal for me the rest of the time (almost WOT..... I drive it pretty hard most times within the speed limit) There were also two instances where I had to pass a vehicle on the back road yesterday that did not happen during the "first run". This was more sporty driving as opposed to hypermiling.

Mileage:

First run........ 33.9 MPG,

Second run.... 33.8 MPG,


Conclusion: The synthetic oil has allowed better MPG in the sense that I can drive normal for me as opposed to "hypermiling" to acheve the same MPG. Secondary conclusion, I don't know why others are only getting 27-28 mpg on the freeway and less around town........ To the OP, as I said earlier 25 mpg is way too low....


It's also my opinion, contrary to many, that the 2.4L should get better mileage that the 2.2L because both cars weigh the same and the 2.4L has more power.... if driven the same the smaller engine is working harder to acheve the same end result...... just my