I have to say that this forum is awesome. You folks really can cover all the bases and I want to thank you for it.

I did not buy my HHR primarily for its mileage. It was a combo of many factors. I am aware that the EPA estimates are just that, estimates. Being almost 48 and having driven for many years in calif with a variety of cars, I also know that there are many variables regarding your MPG.

My tires have 36psi in them. I do not warm the car up. My a/c has been off. My sunroof and windows have been open some of the time. I do not have to sit in traffic idling. I use mobil or shell gasoline and alternate the octane grades.

My driving habits are conservative, I do not banzai off stops. I drive the speed limit give or take a few mph. I have made a few high speed passes around boneheads. I believe that the break in period was done correctly.

22 is the advertised mpg in city driving. I am averaging 16.1 and yes it has gone up a little. The best I have gotten is 19.2 and that was with a 100 mile freeway trip. I reset the DIC each tank.

With the exception of a few of my HHR brothers and sisters, most of you guys are getting killer mileage. 2006's are doing very well. The SS's are doing pretty good by what Ive read. There is someone on the other board that is experiencing the exact same problem I am, he is taking it in to reflash for, if nothing else, peace of mind to eliminate that particular possibility. It is INSANE to have to accept that a 4 cyl car with todays engine management systems is going to get the MPG that I am. I am taking a day off work to try and get it into the selling dealer's shop, at least they wont just blow me off like my local jackass does.

 

Could be a flakey oxygen sensor too, but that usually throws a check engine light. Not always, but usually. At whichever dealer service dept you take it to, politely request that they thoroughly test the oxygen sensor circuit, as well as the oxygen sensor itself. Also request they check the coolant temp sensor circuit. Those are the two Holy Grails of air/fuel mixture.

 

HipHotRod....

I would check for MPG on an Interstate run of maybe 100 miles. Reset the MPG Meter to zero when you enter the Interstate. Get to cruising speed of 65 MPG and set the Cruise Control. Leave the MPG indicator on....don't move it to any other reading. Drive maybe 50-75 miles, observe your indicated MPG turn around and return. As you are exiting notice what the MPG indicator is displaying. If it's anything close to 30 MPG, I would suggest you city driving IF THE REASON.

This method will not give you an absolute, but should be a good indicator.

 

yep, will try something similar. bottom line is the driving that I do 7 days a week is going to equate to JACKED up mileage and Im not happy about it. I will decide to keep it or not soon.

 

Also check the plugs, make sure their clean and gapped properly..

 

The OE plugs in HHR 2.2L and 2.4L are premium iridium tipped type. Whatever you do, don't change them out-- they're better than most after market plugs already.

 

For my setup (Due to all the mods)..
Those stock plugs were the first to go..

I'm using one range colder plugs...
(More moding, more heat, plugs need more insulation)

 

It only has 2000 miles on it, I wouldnt think plugs as the culprits but thanks for covering that possibility. I have noticed the tailpipe a little blacker than I would think it should be. The nutty thing is that these ECM's are so sophisticated, Im certain any sensor malfunction would render a SES code. I need to find a really good dealer that will take the time to go over any and all possibilities.

Here's another thought: The dealer looks up my calibration code and then goes online to see if any updates are available. What if I just request a reflash, in other words irregardless, JUST RELOAD it? Our cars have no adjustments available like older cars. I have to exhaust all venues to find out if in fact something is wrong. All the while spend a grip of money for gas finding out.

 

Have you tried any fuel system cleaner? If not try Lucas Oil brand fuel injector cleaner. It is a petroleum based cleaner so there are no harsh chemicals in it. You will probably want to try to run through two tanks of gas and you might see a little better MPG. Also I have noticed that when I put in 87 octane my mpg goes down, but as soon as I put in 89 - 93 the mpg go back up. And I drive my car like a bat out of hell(granted I drive a cobalt so my car is a little lighter than yours).
I think I read that you are going to put in a drop in K&N filter. That should help out some also.

 

Hey Garth. Yes I am a long standing Lucas fuel treatment user. Ive used it in almost everything I own that has fuel running thru it. I put it in once a month. Yes, hoping that when I get the K&N it will help it too. Thanks...Don